Note: Descriptions are shown in the official language in which they were submitted.
113;~360
The present invention may relate generally to
memory apparatus for use in a data processing system and
particularly to open loop control of stepper motor drive
of rigid disc memory apparatus having special mechanical
control and cooling features.
This application is related to applicant's copending
applications Serial Nos. 324,431, 324,432, 324,433 and 324,434
all filed on March 29/ 1979.
In the prior art, rigid magnetic discs for use with
data processing systems as digital information memory devices
have generally been driven by motors under servomechanism
or closed-loop control. These motors, which were used for
positioning the apparatus that supports the magnetic heads
for writing information onto and reading information from
the disk, were usually linear (voice-coil~ type motors.
Rotary type motors may have be,en used~ but lf so ! they were
not stepping lor stepper) motors as far as is known.
But, stepping motors had been used with non-rigid,
or -floppy--, or flexible disc media, as for example, disclosed
in U.S. patent 4,071,866 which discloses a lead-screw
arrangement for coupling step rotation of the stepping
motor to apparatus which supports the magnetic heads.
Floppy discs are less expensive than rigid discs, but
they have shortcomings which include relatively poor
reIiability and short life, since the magnetic heads are in
mb/~' - 2 ~
contact with the surface of the floppy discs! By contrast,
rigid magnetic discs do not contact the magnetic heads
which -fly on an air bearing relative to the disc surface.
Another problem associated with floppy discs is
that they cannot store nearly as much binary information
as can a rigid disc. One reason for this limited capacity
is that floppy discs usually have a substantially lower
track density (density of concentric rings or tracks which
can be allocated as concentric areas on the surface of
this disc to retain binary information) than do the rigid
magnetic discs. While this is a disadvantage of floppy
discs, a concomitant advantage of floppy discs is that
because of its lower track density, its magnetic head
actuator is sufficiently accurate without c~osed-loop
control. The avoidance of this extra closed-loop or
servomechanism technology (mechanical, electronic, and
electromechanical) provides a substantial reduction in
cost, complexity, etc. On the other hand, although rigid
magnetic discs can store substantially more binary
information than floppy discs, since track density in
rigid discs can be much greater, actuators of rigid disc
magnetic heads usually required closed loop and servo-
mechanism control with its accompanying higher cost,
complexity, etc.
However, there have been designs in the prior art
which have approached but not achieved an open-loop system
I for rigid discs. In the early 1960's, IBM developed a
rigid disc system which employed a d.c. motor and a
mechanical, ratchet-type, detent control. There was
mb/`~ 3
~b.~
:1~3~360
feedback involved, although the type of control may
not be necessarily characterized as closed-loop
control. It suffered from low track density
capacity, mechanical wear, poor reliability, and
other problems. This older technology employed
straddle-erase-- magnetic heads, which were used
to provide clear separation between concentric
magnetic rings of binary information, by using
erase heads on both sides (in the radial direction,
and thus straddling) the read/write head. This
-gap-insurance-- was necessary in the older technology
since head position control (and possibly even with
mb/~c - 3a -
113~
servocontrol) was not that good.
Straddle erase heads are not readily available today
in ''Winchester-- technology (a lubricated, rigid magnetic
disc, with lightly loaded heads in a sealed environment),
which the present invention employs. Although the present
invention uses open loop control with high track density
discs, it is still sufficiently advanced in its control
design to avoid need for straddle erase heads (which, as
noted, are not readily available anyway).
A substantial advance in the technology of computer
disc memories has been achieved by the present invention.
Higher reliability and greater storage capacity character-
istics of rigid magnetic discs are now combined with the
lower cost and less complex characteristics of an open
loop disc drive. The present invention, which is operating
successfully, thus combines the best of both 'worlds-- and
is therefore a solution to these above-noted shortcomings
of the prior art.
In the prior art, there is a mechanical control
extending outward from the Winchester technology sealed
enclosure permitting the locking of the magnetic heads
I upon the -landing zone-- position of the disc, an uncritical
area where information is not intended to be stored. Zero
alignment normally takes place at the factory, and was
usually accomplished by separate control. The present
invention provides a convenient improvement to this zeroing
procedure by permitting the same -landing zone-- lock to
function in the same position as a zeroing control which
provides a zero track reference, and in another position
~b/~o
131360
establishes a safety travel-limit for movement of
the magnetic head support arm during operation of the
disc drive.
Other prior art frustrations related to
precise adjustments of the heads above and below
the surface of this disc, since, as noted, magnetic
heads during operation or spinning of the disc fly
on an air bearing developed by relative motion of
mb/Jc~ - 4a -
O
heads and ambient air. In the past, precision machining
of the multiple pieced supporting structure was required
to provide the precise (about .02 inches) tolerance
required. The present invention provides a solution to
this prior art precision machining problem by employing
shim or spacer apparatus to permit adjustment of heads
relative to disk surface.
Another prior art concern related to mis-alignment
or erroneous orientation of sensing transducers such as
an optical transducer employed in the memory apparatus
when the memory apparatus was being fabricated. In the
optical transducer situation, the spinning magnetic disc
structure could include an optical mask spinning therewith,
and with a toothed or apertured periphery for purposes
of permitting and preventing optical communication in
the coupled optical transducer. The transducer counts
the teeth and thereby generates information indicative of
angular speed and displacement of the spinning shaft.
In certain prior art memory apparatus constructions,
alignment of optical heads with the optical mask and
potential damage to them was a critical problem;because
of the high density of mechanical parts in close
proximity to the location in which the optical transducer
would be positioned. Accordingly, the present invention
is a solution to this problem of the prior art by
providing special keying means for allowing only the
unique and proper insertion, mounting, and orientation
of the optical transducer.
mb/J G
~13136V
Yet another problem of the prior art, and
a problem which is associated not only with this
memory technology, but with virtually all electro-
mechanical apparatus, is the removal of heat which
has been generated by operation of the electrical
and mechanical components of the apparatus.
Normally, a separate mechanism such as a separate
fan is included somewhere within the housing of
the apparatus to create a draft or flow of air
which provides the necessary heat transfer and
stabilization of temperatures within the
apparatus housing. But, this additional fan
mb/Jc - 5a -
li313~iO
requires additional space, additional cost, additional power,
and generates additional heat which is the precise problem
it is trying to compensate. Accordingly, the present
invention is an improvement in this area of temperature
control by making use of rotary or pivotable motion already
present for other purposes and synergistically providing a
cooling effect without addition of separately powered fan
apparatus.
The foregoing and other problems of the prior art
are attended to by solutions described and embodied herein,
as will be elaborated on hereinbelow.
SUMMARY OF THE INVENTION
The present invention relates to the removal of
unwanted heat energy generated by electrical and electro-
mechanical components of a system, such as a memory system
for use in a digital computer, by creating a circulation
of ambient air through the enclosure of such electrical and
electromechanical components. The apparatus for creating
this cooling effect draft is constructed from components
already contained within such enclosure, which components
would not ordinarily be used for this purpose, whereby a
synergistic effect is obtained.
~ In a particular embodiment of the present invention,
the motor which is used to drive a spinning magnetic disk
in memory apparatus for use with a data processing system
is also used for cooling purposes. There is flow structure
as, for example, fan blades mounted on the spinning shaft
of the disk drive motor for creating a draft of ambient air.
mb/ l - 6 -
~i3~
In a further feature of the present invention,
duct work is employed in cooperative connection with the
flow structure for orienting the draft of cooling air
against certain components and structure within the enclosure
that would otherwise require special fan apparatus to
maintain these components within their operating temperature
range.
It is thus advantageous to employ the present
invention in any electromechanical apparatus having a spinning
shaft which would otherwise not be used for cooling purposes.
It is a general object of the present invention to
provide improved memory apparatus with improved cooling
techni~ues for use in a data processing system, the improve-
ment achieved by incorporating draft or flow structure on
the spinning shaft which drivesthe magnetic disk of the
memory apparatus, suc~ spinning shaft otherwise not employed
for cooling purposes.
Specifically, the invention relates to memory
apparatus for a digital computer system comprising in
synerglstic combination: at least one spinable magnetic
disc for recording digital information; sealed housing means
for enclosing at least the magnetic disc; rotational motor
means including a spinable shaft sealably mounted
through the sealed housing means for spinning the magnetic
disc; and cooling means comprising flow means mounted on
the spinable shaft external to the sealed housing means
for causing flow of ambient air to cool selected portions of
the apparatus external to the sealed housing means.
mb/ ~ - 7 -
.
-.~
~131;~60
. .
O~her objects and advantages of the prcsent invention
will be understood after re~erring to the detailed description of
the preferred embodiments and to the appended drawings wherein:
. ' . ,
BRIE:F D}'SCRIPTION OF ~r~E DRA~ GS
S Fig. 1 is a perspective view of the magnetic disc
memory apparatus;
/ Fig 2 is a schematic illustration of the magnetic disc
memory apparatus of Yig. l;
Fig 3 is a detailed view of the pulley, coil spring,
O and metal band coupling arrangement of the magnetic disc memory
apparatus of Fig. 2;
Fig. 4 is a scnematic illustration of the stepping
motor showing viscous inertia damping apparatus attached thereto;
Fig. S is another view of the viscous inertial damper
of Fig. 4;
Fig. 6 is a schematic illustration of pivotable arm .
structure and manually operable pivot arm control structure
employed in the magnetic disc memory apparatus;
Fig. 7a and Fig. 7b are schematic representations of
O the manually operable pivotable arm control from a view in the
same direction as Fig. 2, showing its multiple position capabil-
ity;
Fig. 8 depicts an alternative embod;ment of the band
coupling arrangement of the memory apparatus described herein;
Fig. 9 depicts another alternative embodiment of the
band coupling and magnetic head support arm apparatus of the
magnetic disc memory structure disclosed herein;
Fig. lOa, Fig. lOb, and Fig. lOc show an optical trans-
ducer system employed in the memory apparatus described herein
O and the arrangement by which its orientation during mounting and
assembly is constrained to be accurate; and
, , .
1~3136g~
Fig. 11 is an exploded representation c,f the
constant speed motor which drives the spinning magnetic
disc, and fan blades and duct work associated therewith,
to obtain a cooling effect for other components in
magnetic memory apparatus described herein.
~:~ mb/ 9
~3:136V `
DESCRIP'rlON OF THE PREFE~RED E~;BODII~Æ1~'rS
. .--
Referrîng to Fig. 1, a perspective view of the rigid
magnetic disc and its enclosure is presented. This apparatus can
be characterized as-"Winchester technology~ since it emp]oys a
; sealed, non-removable, lightly-loaded head, for a lubricated rigi
disc. The cnclosure is in co~unication with the ambient atmos-
phere through an air filter (not shown). The enclosure is neces-
sary to maintain a relatively controllable ambient atmosphere for
the spinning magnetic disc and the magnetic heads flying on an ai
bearing relative to the disc. l~ousing or base 100 provides this
required seal; constant speed motor 110 drives disc 200 which wil
thus spin about its spin axis; and, stepping motor apparatus 120
provides step rotational motion to pivotahle arm 210 and carria~e
arm 220 so that magnetic heads 230 can be
curvilinearly displaced in a plane parallel to the surface of dis
200.
Referring to Fig. 2, magnetic disc 200, which is a .
rigid ana not a "floppy" disc, is pivotably mounted about zxis
or shaft 201, which shaft is driven by constant speed motor 110.
Constant speed motor 110 is rotatably or pivotably mounted around
shaft or axis 111, (the housing of the motor being fixedly
mounted to the base and the motor shaft being rotatably or pivot-
ably mounted therein), axis 111 and axis 201 being substantially
parallel. Belt 240 is connected from shaft 111 to shaft 201
thereby providing drive from motor 110 to disc apparatus 200.
Circular dashed line 250 represents a toothed-periphery
of an optical mask rotatably mounted with disc 200 about shaft
201 (and hidden from view in this figure). Optical transducer
structure or system 260 is shown adjacent optical mask 250,
whereby optical communication within the sending and receiving
devices of optical transducer 260 is permitted and prevented by
passage of the toothed periphery between such devices. Further
detail of optical transducer system 260 is shown in Fig. 10a,
'
., -10- -_
1131360
. I
lOb, and lOc to be further descrihed herc~nbelow.
Pivotable arm 210 pivots about pivot axis 211, motion
of pivot arm 210 thus being parallel to the surface of rigid disc
200. ~xtending from or cantilevered from pivotable arm 210 is
carriage arm 220 which supports magnetic heads 230. Essc-ntially
conaruent structure hidden from view by carriage arm 220 and
disc 200 is another carriaqe arm supporting two other magnetic
heads (thus not shown). As disc 200 spins about axis 201, mag-
netic heads 230 and those on the opposite side of the disc as
well ride on an air bearing created by draft of the spinning disc,
thus there is no physical contact between maqnetic heads 230 and
disc 200 when disc 200 is spinning. This air bearing is in the
neighborhood of 19 microinches. Because of pivotable motion
about pivot axis 211, maqnetic heads 230 are curvilinearly dis-
placed in a plane parallel to the plane of rigid disc 200.
Pivotable arm 210 is made to pivot about pivotable axis
211 which is substantially parallel to axis 201, by the drivinq
force of stepper motor 120 which is pivotably or rotatably mounted .
to the base of the memory apparatus (the housing of the motor
beinq fixedly connected to the base of the memory apparatus and
its shaft 121 beinq step-rotatable therein~. Stepper motor 120 is
shown in operative connection with pivotable arm 210 through
coupling bands 280 and 290.
Referring still to Fig. 2 and also to Fig. 3 where the
detail is more readily seen in this larger view, bands, preferably
metal bands, are apertured and mounted around fixedly connected
bosses 281 and 291 respectively, these bosses or points heinq
non-adjacent and alonq the surface of the portion of the pivot-
able arm opposite from axis 211. The holes in the bands are
larger than the bosses to permit some play or movement. Rubber
or pliable qrommets or washers 293 are press fit over their
respective bosses as shown to provide proper spacinqs ~nd .
anchorings. ~
., ,
I j ..
-- . .
~IL3:~3ti~
In a specific embodiment, the surface 292 of
pivotable arm 210 at the opposite end from pivot axis 211
is a portion of a circular rim. Metal band 280 and metal
band 290 lie on the surface of this circular rim and
cross or overlap without touching each other. Metal band
280 is similarly connected at its other end to pulley
271 at boss or point 282. Pulley 271 has a rim-like
peripheral wall seen on end in Fig. 3, mounted around a
disc like member lying in the plane of the drawing, which
is mounted about shaft 121, the shaft of stepper motor 120.
Thus when stepper motor 120 operates, shaft 121 step
rotates in response thereto, and since pulley 271 is
fixedly attached to shaft 121 and is mounted therearound,
pulley 271 likewise step rotates. Coil spring 270 is
mounted around shaft 121 and is fixedly connected at one
end of the spring to pulley 271. The other end 272 of
spring 270 protrudes through an aperture in the wall of
pulley 271 in an unconstrained manner, and is adapted
to receive the aperture at the other end of metal band 290.
In other words, the aperture at the other end of metal
band 290 is similarly attached to protruding end 272 of
coil spring 270, in a manner that permits some play or
movement. The attachments need not have this play or
movement, and could have been fixed attachments, but
the apertures being larger than the bosses do permit
automatic accommodation to some unwanted but unavoidable
motions that might occur.
If the bias on spring 270 is in that predetermined
-A- direction to cause tension upon metal band 290 pulling
mb/J~ - 12 -
~3~36l~
against fixed stop 291, then due to the transmission
of force through pivotable arm 210, the fixed stop
281 will pull against metal band 280 which thus pulls
against fixed stop 282. Accordingly, the dynamics
and equilibrium of the configuration show that a taut
condition is continually applied to both metal bands,
which metal bands are chosen to be both flexible, but
substantially inelastic in the taut biased directions.
In the preferred embodiment, these metal
bands are constructed from ELGILOY~ alloy, the wall
surface of pulley 271 almost circular, and the
surface of 292 an arc of a larger-diameter circle.
The flexible bands are thus constrained in a manner so
mb~c - 12a -
3~-
that almost half of their total surface area is always
in contact with one and the other circular support surfaces.
Because of this continually taut but non-longitudinally
flexible configuration, step rotation is accomplished with
virtually no hysteresis and almost total repeatability.
(By no hysteresis, it is meant that: if each step of the
stepper motor could be conceived as being comprised of
successive infinitesmal increments, then each successive
increment of stepper motor shaft motion is instantaneously
converted into a corresponding successive infinitesmal
increment of motion of the pivotable arm.)
Another feature of this preferred embodiment is
built-in temperature compensation~ Normally, the magnetic
disc is constructed from a metal such as aluminum. The
carriage arm is also constructed from metal, and flexure
220a which holds the magnetic heads may be constructed
from steel. Therefore, as ambient temperature changes,
for example increases, the disc radial dimension and the
radial dimension of flexure 220a both increase, and in
; 20 the case of this configuration in opposite directions that
accentuate the magnetic head offset which occurs. Spring
270 and bands 280 and 290 also expand with temperature
increases. Therefore spring 270 is intentionally oriented
so that its protruding end 272 pulls against the bands in
that direction that will cause the magnetic heads to have
minimal offset as temperature changes, thus providing
temperature compensation; (the steel band expansion and
contraction will tend to pull the heads in an outward
generally radial direction as temperature increases and
mb/ - 13 -
1..,
~13~360
will tend to displace the heads in an inward generally
radial direction toward the disc's axis 201 as temperature
decreases).
Referring next to Figs. 4 and 5, stepper motor 120
is shown in outline form and in the preferred embodiment
is a Superior Electric type M062 motor. Shaft 121 of
stepper motor 120 connects to viscously-coupled inertia
damper 129. Slug or fly wheel 122 is shown in dotted
line construction internal to the housing or enclosure
of the damper. There is also viscous fluid 133 such as
silicone internal to the damper housing. The enclosure
containing the slug is evacuated through aperture 131,
mb/Jo - 13a -
~31360 .
.
through which the silicone or other viscous fluid is
thercafter injccted. There is a rigid connection between shart
121 and the darnper hol~sing, by way of clamping struc~urc 132
and 134, where slug or flyw~leel 122 is arranged to be free
to rotate about shaft 121 within the damper enclosure. For
an~ular accelerations, such as those which occur when the s~c-pper
motor starts and stops, there is relative movcment between the
flywheel and viscous media, thus providing the desired damping.
But for constant velocity motions, the viscous media and flywheel
move together, the relative motion ~herebetween then being zero,
and the net damping afiect upon motion charactexistics of the
stepper motor then being minimal. Protuberance 130 is an optical
mask or tab which is employed in conjunction with an optical
transducer (not shown) used as a "home switch". This is a switch
which is activated or deactivated when the damper housing is
returned to a reference position, and will be discussed more full
hereinbelow. This type of damper is commercially available.
Referring to Fig. 6, pivotable arm 210 connects by way
bearings 211, pin 620, nut 621, spring 622 and shim or washer
structure 212 to a portion of base 100 designated 101. In addi-
tion, there may be other pieces of structure internal to arm 210
and base 100 (and thus not shown) which are added to each other
to make up the overall pivotable arm pivot axis length. Each
dimension, if a shimming procedure was not used, would have to be
precisely machined. The dimensions of each piece of structure
are chosen so that, in the preferred embodiment of the present
invention, shimming is always needed. The shims or washer are
insertable one upon the other to adjust the position of pivotable
arm 210 relative to base portion 101. This adjustment permits
the carriage arm and therefore the magnetic head structure to be
easily and precisely set.
Motion of pivotable arm 210 is into and out-o~ the
plane of the drawing about axis 211. Interacting surface 292 is
at the end of the pivot arm opposite pivotable axis 211, and is
,~ 11 , ._. '
¢
. 1~3~36~
the surface for interacting with band-coupling earlier describe~.
Extending or protruding downwardly or in a direction towards base
portion 101, are two tabs 604 and 605.
Also shown in ~ig. ~ is a rotatably mounted pivotable
arm control 606. The rotatable mount on base portion 101 is
shown at 607. Stops 601 and 600 are shown protruding up fro~
carriage arm control 606 in a manner designed to engage tab 604
on one side thereof and tab 605 on an opposite side thereof.
Shaft 602, rota~ably mounted at 607, rotates upon manual applica-
tion of force at or near protuberance 603 in directions into or
out of the plane of the drawing. The connecting structure 610
between protuberance 603 and shaft 6~2 is springyor flexible to
permit application of a torsion force on shaft 602 when protu-
berance 603 is mated into certain apertures in the base, to be
described below. Protuberance 603 and its cornecting struc,ure u
to mount 607 is external to the sealed housing of the disc drive.
Prior to referring to Fig. 7a and Fig. 7b, allocation-
of disc surface area shculd be reviewed. In the present inven-
tion, the magnetic heads are two per disc surface, (and can have
two usable surfaces per disc), the heads being separated from
each other and disposed along a radial line of the disc. Thus,
directing this discussion to only one disc surface for clarity of
illustration, there are two separated "bands" of concentric track
on the disc surface, that are utilized for recording digital in-
formation. The inner band has its "landing zone" including
its "landing track" adjacent its innermost track, and ihe outer
band has its "landing zone" including its "landing track" in the
separation bet~een the two bands; The landing zones are track
areas on the disc surface that are not used for recording digital
information, where the magnetic heads are thus permitted to ma~e
physical contact ("land"~, when the disc is not spinning. Near
the inner periphery of, but just outsi~e of, each band, there is
a track designated as "home" ~or the home track), which is the
-15-
. '
.
L3i3tiV `
,.
refc-rence position referred ~o earlicr in the discussion of the
home switch and protuberancc 130~
Referring, t11en, to Figs. 7a and 7b, schemat;c views of
the operation of the control arm of Fig. 6 are shown, the views
being taken in the direction of shaft 602. In ~ig. 7a, control
606 is shown loc~ed in the landing 70ne~s) position. Protuberanc
603 is restrained by an aperture (not shown) in the base, and
causes tension to be applied via flexible structure 610 and stops
600 and 601 against tabs 604 and 605 respectively. Carriage arm
0 210 tand thus the m,agnetic heads attached thereto) being attached
to tabs 604 and 605, are thus locked i-n this position. In this
pOSition the magnetic heads are in their respective landing 70nes
and lie in their respective landing tracks. The landing tracks
are chosen so that when the magnetic heads are on these tracks,
they will have no influence upon any ring of either
band.
The landing track is thus another reference track~, and
is actually the reference from which its respective home ,rack is
determined, by counting a predetermined number of tracks and
setting the home transducer and protuberance 130 accordingly.
Thus the machining of both the round portion of stop 600 and tab
604 is critical, since these components essentially control the
location of the landing track, as shown in Fig. 7a. Fig. 7a also
shows the locked position in which the apparatus is shipped, sinc~
the heads and the disc can do no severe damage to each other in
this position.
Referring to Fig. 7b, control 606 is shown rotated to
its operating position, and again locked by protuberance 603 in
conjunction with another aperture in the base. In this position,
tab 604 (and thus the carriage arm) has a range of motion from
stop 601 (and is shown touching stop 601) to the "flat" or
"relief" of stop 600. These stops now present travel "crash-
limits" for the magnetic heads. These prevent movement of the
~ .
-16-
. ', '.
.~ .
~13:1360
carriaoe alm ~o harlnful ~xtrcm~s that could cause darnage, ~e g.
off the surrace of the disc or a9ainst the cen~ral shaft). ~rhese
limits can be chosen so that the magnetic hcad normally associate~
with one band does not travel across the ccntral landing ~one J
between the bands to the other band, although another, rubberized,
"soft-stop" (not shown) is provided for this purpose.
It should be appreciated that in the factory, prior to
shipment, control 606 is used to move the pivotable arm into the
locked position shown in Fiq. 7a. riovement and lockinq of the
carriage arm and the accompanying magnetic heads to this position
is a convenient and reliable way to establish the landing track(s
from which the home tracX(s) is referenced.
Next, with regard to Figure 8, an isometric view of an
alternative embodiment to the band coupling device is depicted.
Referring back to Fig. 3, the two metal bands as shown in an
edge view are not defined to have any specific confiquration,
'' . ,, / -. .
. /
. / . ' .,
. .
-17-
. . ' ' i '.
~ , I
11313~0
bu;, in thc preferred cmbodimcnt are two scparate gc-nerally rec-
tangular metal bands. i~owc-~er, in Fi~. 8, a config~ration is
depicted, which is desi(~ned to prc-vent torqueing effccts, since
the forces (2~ = F+F) arc syl~netrically or evenly distributed.
In Fig. 3, with the overlapping separate rectangular band arranyc-
ment, where band 290 is intended to be depicted as lying
above or higher than band 280, application of fol-ce on these
bands by spring 270 creates torque, however minimal, which would
tend to cause the portion of pulley 271 near spring tip 272 to be
elevated from the plane of the draving and tend to cause the
portion of pulley 271 near fixed mount 282 to be depressed into
the plane of the drawing. This eflect proved to be of minimal
concern in the apparatus of the present invention, and -did not
adversely affect operation of the present invention. But, for
; other embodiments of the present invention where such torqueing
might be a coupling problem, Fig. 8 depicts a solution. The
configuration of Fig. 8, where hole 291' is adapted to receive
fixed connection 291 and aper.ure 272' tnot shown) is adapted -to .
receive sprinq end 272, where holes 281' are adaPted to receive
j su~orts 281 and hole 282' (not shown) is adapted to receive
I su~Port 282, qenerates svmmetrical forces as shown where unwanted
torque effects are not permitted.
In Fig. 9, a schematic, alternative embodiment of the
Support arm for the magnetic heads, and structure for moving the
magnetic heads relative to the rotal:ing magnetic disc is shown.
Endless metal band or closed loop band 980, shown on edge is
tautly ~-rapped (and can be spring biased to achieve tautness)
around two pulleys 981 and 982. (~lternatively, the band need
not be closed on itself as long as it is tautly wrapped.) One of
these pulleys, for example, 981, is driven by stepper motor 120.
Structure 910 is fixedly connected to band 980 as shown, rom
which structure 920 is cantilevered. Magnetic heads shown
generally at 930, are linearly translated by virtue of the
stepping motor movement in a radial direction adjacent
spjnning magnetic disc 900. This ~ltern~tive ~mbodiment does
r
not show bearing and guide xails and similar structure
normally used for supporting structure 910, in order to
improve clarity of presentation. However, Fig. 9 does
illustrate that even with use of a stepping motor, motion
of the magnetic heads relative to the surface of the
spinning disc need not be curvilinear or circular but
can, in fact, be linear and radial. Axis 985 can be,
but need not be parallel to axis 983 and 984. (U.S. Patent
3,946,439 shows a similar, but different, construction
as applied to floppy discs, where disc contact is essential.)
Next, with regard to Figs. lOa, lOb, and lOc, the
optical transducer system used for measuring angular
displacement of the rigid magnetic disc from a fixed
reference is shown. Figs. lOa and lOb show how the
transducer would be inserted and Fig. lOc shows its rotated
and locked positions. Upright member 268 is shown
supporting optical transducer 261 in proper alignment
with toothed or apertured optical mask 250 (rotatably
mounted around axis 201). The optical transmitting and
receiving devices are contained within transducer 261
above and below mask 250. The upright member 268 is
supported on lip or base lip 262, which is apertured as
shown by apertures 266 and 263. At extremeties of these
respective apertures, keying holes 265 and 264 are shown
asymmetrically displaced (these keying holes do not lie
on a line of symmetry of this base lip structure) in order
to prevent 180 mis-alignment. A ring lOOa of base
structure 100 is shown in Fig. lOb with aperture 160 adapted
to receive optical assembly 260. Mating screws 161 and 162
mb/~O 19
~1;31360
are positioned to receive keying holes 265 and 264
respectively and thereupon rotational motion about
center 267 will propexly align optical structure 260
xelative to mask 250 by the sliding of mating screws
161 and 162 along the periphery of apertures 266 and
263. This motion essentially swings the optical head
about the edge of mask 250, without contact or damage.
The density of other components in this vicinity is
high, and visibility is limited; thus, if the keying
arrangement were not provided, mis-insertion could
cause damage to the optical heads. The rest position
or the orientation position, when the optical transducer
is properly aligned, occurs when apertures 269 and 269'
mb/~ - l9a -
I ~13136~
line up with screw holes 270, into which screws (not .s},own) are
tightenc-d to secure the transducer apparatus in pl.3ce.
Referring next to exploded isometrie Fig. 11, eonstant
speed motor 110 of FigO 2 is shown with shaft 111 protruding ther _
from at both ends. As noted earlier, shaft 111 is mechanieally
linked with dr;ve belt 240 which causes pivotable motion of shaft
201 and therefore pivotable motion of magnetic dise 200. ~o~ever,
availahility OL this rotary motion external to the sealed enelo-
sure but within the chassis of the mc-mory apparatus is further
employed to accomplish another separate and distinet operational
function in a synergistically efficient manner. Shaft 1]1 is
eoupled to dralt structure, such as for example fan blades ]12,
which creates draft or flow of ambient air ex~,ernal to dise drive
enelosure or base 100, but within the chassis of ,he overall
memory apparatus system. This ambient air flow is channeled by
air directional strueture 11' in a desired direction to permit
cooling of electronic and other components employed within the
overall mc-mory apparatus system. (It should be understood that a .
dise drive sys.em employs eleetronie eireuitry 500 sueh as power
supplies, amplifiers, and other circuitry`external to the en-
closed disc, as suggested in Fig. 11 and which reguire cooling.)
Tne constant speed motor is a single phase AC induction
motor with equivalent inertial load of about 23 lb. in2 and viseo s
load torgue of about 1.4 in lb. at a speed of 3840 RPM, and in
this partieular instanee is manufaetured by Robins and Meyers
Company. There is extra motor power available to run the cooling
apparatus, since less than full power is used by the dise when
running at operating speed; the extra motor power is needed when
dise speed is being inereased from zero to operating speed.
~ eferring to all figures in coneert, the present inven-
tion may be embodied in yet other specific forms without depart-
ing from the spirit or essential eharaeteristies thereof. Alter-
native embodiments of the band coupling device and the magnetie
. . .
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~'13~366~
l)cads supportir,g apparatus have been shown. The optical mask
could be a slotted disc or some other apertured mas~ apparatus;
in fact, the transducer system need not be optical and for cxam-
ple cou~d be magnetic, employing permanent maanets and pick up
coils where the same mis-alignment problem would have to be
solved. The coupling bands need not be metal, but could be made
from other material, plastic, for example. However, ten,perature
compensation might not be achieved, even if the magnetic head
support was also made of the same plastic, and reliability would
suffer. The duct work of the cooling apparatus can be multi-
directional.
The present embodiments are therefore to be considered
in all respects as illustrative and restrictive. The scope of
the invention is indicated by the appended claims rather than by
the foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are therefore
intended to be embraced therein. .
1. -
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