Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates Jo a transducer assembly for a
magnetic recording system such as a disk drive. More
particularly the invention relates to an assembly where the
transducer is dynamically loaded onto a rotating disk.
In digital systems, such as in a data processing
apparatus, disk drives are used as the means for storing
large amounts of data that can be quickly read into or
written from a computer's main memory. In a disk drive, a
disk, having a magnetic coating on its surfaces, is rotated
I on a spindle at a predetermined speed. An electromagnetic
transducer, also called head, is positioned in close
proximity to one of the disk surfaces at a predetermined
distance from the spindle to either read data it
playback) or write data (i.e., record) along the circular
track defined on the disk surface by the rotary motion of the
disk with respect to the transducer. By controlling the
position of the transducer, a plurality of concentric tracks
on the disk surface are defined.
The head is mounted on an aerodynamic member, usually
walled slider/ which is designed to ride over the air flow
treated by the rotating disk in order to maintain the head at
a predetermined distance from the disk surface. To increase
the storage density of the disk staller head/slider
assemblies have been used in order to increase the flux
density and reduce the area required to store one bit of
information.
The slider is mounted on an actuator arm which in turn is
mounted on an actuator motor. The actuator motor moves the
arm to successively position the head at predetermined
locations (ire , tracks). Both linear and rotary actuator
S motor/arm assemblies have been used. In a linear assembly,
the actuator arm, and therefore the head, is moved linearly
along a radius of the rotating disk, while in a rotary
assembly, the actuator arm rotates along an axis parallel to
the disk spindle at a point close to the outside rim of the
disk. In either case, the slider is suspended from the
actuator art, in order to allow the slider to assume the
correct attitude over the air bearing, and the suspension
support/slider assembly is cantilevered from the more rigid
actuator arm. The motion of the slider can be resolved along
three mutually orthogonal axes called the pitch, roll and yaw
axes. The pitch axis is defined as the transverse axis of
the slider, the roll axis is defined as the longitudinal
axis of the slider and the yaw axis is normally defined as
the vertical axis, assuming that the slider is placed on an
horizontal plane, and is mutually orthogonal with the pitch
and roll axes. To allow the slider to move freely over the
disk surface the cantilevered suspension must provide a low
spring rate along the yaw axis. To this end, an elongated
cantilevered leaf spring is used. The geometry of the can-
tilevered spring, however, provides low stiffness jot only along the yaw axis ox the slider, but also in a direction
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transverse to the sprigs longitudinal axis. This lack of
lateral rigidity results in a low frequency resonance
characteristic for the cantilevered suspension. This means
that, in response to lateral forces exerted on the suspend
soon, the suspension vibrates about its nominal position and consequently interferes with the proper positioning of the
head at the selected track. This lack of lateral rigidity
might be tolerated in applications using a linear actuator
arm since the nominally linear motion along the longitudinal
axis the cantilevered suspension spring minimizes the
development of lateral forces. However in applications
requiring a rotary actuator arm, the combination of acute
motion and centrifugal force unavoidably generates lateral
forces on the cantilevered spring. These lateral ours push
the head off its nominal position and interfere with its
proper operation. The weight of the suspension assembly,
i.e. the suspended mass, further adds to the resonance
problem, as well as to the torque requirements of a rotary
actuator motor.
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SUMMARY (OF THE INVENTION
The present invention provides a transducer module
comprising: a housing having a tubular wall terminating at one
end with an opening, said housing having two slots positioned
longitudinally on said wall at diametrically opposed locations,
a -transducer slider; a suspension diaphragm having inner and outer
frames coupled to form a flexible gimbal, said inner frame having
a bridge spanning a central inner frame opening and having a
dimple in its center, said suspension diaphragm being positioned
across said housing opening and being attached to said housing
at two diametrically opposed places in proximity of said housing
opening, said slide,- being connected to said bridge on the surface
facing said housing opening; a suspension pickup member connected
to said bridge on the surface opposite said slider; a load
diaphragm h~vina inner and outer frames coupled to form a flexible
gimbal having a central window, said load diaphragm being attached,
at a predetermined distance from said suspension diaphragm, to
said housing at two diametrically opposed places on said housing;
a load transfer plate disposed across said load oiapllragm window
I and attached to said load diaphragm inner frame, said transfer
plate having on one surface a -tab adapted to be inserted in said
suspension pickup member and on an opposite surface a load pickup
member; an unload diaphragm ho Nina outer frame and a pair of
inner legs, said unlead diaphragm being attached at a predator-
mined distance from said load diaphragm to two diametrically
opposed pklces on said housing; and an unload beam disposed on
said unload diaphragrll outer frame an-l secured to said inner lets,
said unload beam having a central tab adapted to be inserted in
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said load pickup member, said unload hem having its two opposite
ends protruding from said housing wall -through said two slots.
This invention also provides an actuator arm assembly
comprising: an actuator arm adapted to move across a Starkey disk;
a slider, having pitch, roll and yaw axes, carrying an electron
magnetic transducer and having an air bearing surface in the plane
of said pitch and roll axes; a housing adapted to be fixed to and
carried by said actuator arm and having at least one major Opening
in a first plane along passage of said slider there through;
a suspension diaphragm attached -to said housing in proximity of
and in a plane parallel to said opening and having a central
portion adapted to- carry said slider, said slider being attached
to said central portion; a load diaphragm attached to said housing
at a predetermined distance from said suspension diaphragm, said
load diaphragm being reloaded to exert a predetermined force to--
ward said opening and adapted for urging said slider to a pro-
determined position relative -to said disk; and means for coupling
said load diaphragm to said suspension diaphragm said diaphragm
having relative geometries sufficient to allow each diaphragm
to pass through the plane of the other without interference, in
response -to opposing forces exerted on said suckler.
This invention further provides a transducer module for
a magnetic recording system, said module having a transducer there-
in and being adapted to be attached to en. actuator arm for use in
positioning a transducer at a st'lect('d location on a recording
surface, CompriSinCJ: a housing adapted to be carried by said arm;
a transducer slider on tush said transducer is mounted, and said
slide; havirlg an air bearing surface; moans or suspendincJ said
Lo
slider from said housing; means for reloading said slider lo,
extend said slider from said housing toward said recording surface
means adapted to cooperate with said housing for selectively us-
loading said slider to retract said slide from said recording
surface; and means connecting said means for unloading with said
arm to selectively retract said slider, wherein a portion of said
muons for suspending passes through a portion of said moans for
reloading upon the retraction of said slider from said recording
Sirius.
This invention further provides a transducer module for
a disk drive having a magnetic read/write head comprising a
slider which supports the head at a predetermined distance from
a rotating disk on an air bearing; a flexible gimbal on which
said slider is mounted; a protective housing in which said flexible
gimbal is scoured; a second flexible gimbal scoured within said
housing said second flexible gimbal being preloGded to bias said
head to a first position toward said disk through a pivot enabling
said slider lo properly position itself and said head thereon in
resporl~e to the air flow a the surface of said disk; and unloading
means for selectively retracting said head to a second position
within the boundaries of said housing through a second pivot,
whereby said housing protests said heckle en in -the second position
and such that a portion of said first gimbal passes through a
portion of said second gimbal when the heed is moved from said
first position to said second position.
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A better understanding of the features of the present
invention may be obtained from the accompanying description
used in conjunction with the drawings in which:
Figure 1 is an exploded view showing a rotary actuator
arm, mounted on a rotary actuator motor, supporting the
housing holding the transducer assembly of the present
invention;
Figure 2 is an exploded view of the transducer module;
Figures 3 A-D show the forming operation for reloading
the load diaphragm.
Figures 4, 5 and 6 are cross-sectional views of the
transducer module showing the range of motion of the various
parts from the fully loaded to the fully unloaded transducer
positions.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to Figure 1, there it shown the dynamically
laudably transducer module 10 of the present invention. For
simplicity, only housing 12, read/write head 50 and a portion
of the unload beam are shown. The details of transducer
module 10 will be described Gore fully hereinbelow, suffice
it to say for now that the read/write head 50 and its
suspension assembly are contained within housing 12, and that
the head is loaded and unloaded onto a surface of a rotating
disk, not shown, by the relative movement of an unload beam
up and down the two slots 16 cut on opposite sides of housing
12. Housing 12 is provided with a lip 13 which-is wielded or
otherwise fastened, to end portion 22 of arm 20. Housing 12,
and therefore head 50, is shown facing upwardly, but it
should be understood that housing 12 may face any prescribed
direction. Arm 20 is coupled to shaft 30 of rotary actuator
motor 31 and has an opposite counterweight end 26 extending
past the shaft to balance the weight of the arm. Arm I has
a first portion, starting at the shaft, of uniform
predetermined thickness and a second portion of tapering
thickness connecting to end portion 22 of uniform thickness.
The plane of the surface of end portion 22 to which housing
12 is welded is below the plane of the corresponding surface
of the first portion of arm 20.
Leaf spring 32 is provided with a base end 33 and a
forked end 34. vase end 33 is attached to the first portion
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of arm 20 and, due to the tapered thickness of the second
portion of arm 20, leaf spring 32 is effectively cantilevered
from the attachment region. The forked end 34 has an inner
semi-circular edge which clears a corresponding semi-circular
side of housing 12. Each of the two ends 14 of the unload
beam protruding from housing 12 is welded, or otherwise
fastened, to the forked end 34. Leaf spring leaf 32 has a
raised portion located midway the two ends for forming a ramp
35. Cam 40 is supported on foot 62 by support plate 44 which
is mounted on the casing of actuator motor 31~ Cam 40 is
used during the unload operation when the actuator arm 20 is
rotated by motor 31 until the lower surface of cam 40
contacts the ramp 35. Continued rotation of arm 20 causes the
leaf spring 32 to be pushed in towards the tapered surface of
arm 20 and so pivot at the base end 33, which depresses the
unload beam. This, as will be explained in more detailed
hereinbelow, has the effect of pulling the read/write head 50
away from the disk in a direction per perpendicular to the
disk surface. During the load operation the opposite steps
take place, thus the read/write head 50 is free to be pushed
back toward the disk surface by the assembly within the
housing 12.
Referring now to Figures 2 and 5 there is shown in
greater detail the components of transducer nodule 10.
25 Read/write head 50 comprises magnetic Coxes 51 and wires 53
forming coils around the cores. Slider 52 has a compound
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surface 54 which is adapted to respond to the flow of air
between the transducer and the moving disk surface to
properly position itself and the read/write head 50 over the
disk, i.e. to float over the disk surface on an air bearing.
Slider 52 is attached to a suspension diaphragm 60. Slider
52 has a rectangular cut out portion 56 which mates with
bridge 62 of suspension diaphragm 60. The horizontal surface
57 of cutout 56 mates with bridge 62. The shape of bridge 62
and particularly prongs 64 enable bridge 62 to frictionally
engage the vertical sides of cutout 56 and help to retain
slider 52 on bridge 62, in addition to an epoxy agent present
between the horizontal surface 57 of cutout I and bridge
62.
Suspension diaphragm 60 has inner and outer frames 65
and 66 respectively, connected at two diametrically opposed
places by bridges 67. The outer frame 66 is attached in two
places in the region of cutouts 68 to attache men jabs 10~ of
housing 12 by any convenient means such as welding. Cutouts
68 mate with a complementary portion of tabs 100 and thus
serve as alignment guides. Suspension diaphragm I thus
forms a gimbal and with this arrangement slider 52 is free to
rotate about the pivot formed by dimple 61.
Attached to the opposite side of the central region of
suspension diaphragm bridge 62 is a suspension pickup 72
having a dimple 74, facing toward bridge 62, on its
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horizontal spanning member. The function of suspension
pick-up 72 will be described in Gore detail below. Suffice
it Jo say here that it is used in the unloading of head I
Load diaphragm 76 is similar to suspension diaphragm 60,
except for the lack of a central bridge. It has an inner and
outer frame, 78 and 80 respectively, connected by bridges 79,
and two cutout regions 82 which mate with a complementary
portion of attachment tabs 112 on housing 12, and is attached
to tabs 112 by welding in the region of cutouts 82. Load
diaphragm 76 is shown flat for simplicity, however it actually
is preluded co supply the countering force required to
keep slider 52 at the correct separation from the rotating
disk. This is explained in more detail hereinbelow, suffice
it Jo say here that the preluding is effected by bending
outer frame 80 of load diaphragm 76 upwards about the axis
connecting cutouts 82, and by bending inner frame 78 downward
about the same axis connecting cutouts 82. A tongue 83
located on inner frame 78 is bent to hold transducer wires 53
and provides strain relief to prevent wires 53 from loading
slider 52.
A load transfer plate 86 forms a spanning member on the
inner frame 78 of load diaphragm 76. It is welded, or
otherwise attached, in two places on frame 78. Load transfer
plate 86 has a hollow central resin into which a horizon
tally offset transfer plate tab 88 projects from one side of
the spanning member. When fully assembled, transfer plate
tab 88 is inserted within the region enclosed by suspension
pick-up 72. The translation of forces from the load transfer
plate 86 to slider 52 ours at the interface of transfer
plate tab 88 and suspension diaphragm dimple 61. A U-shaped
load transfer plate pick-up 90, having a dimple 92 on its
horizontal span, is welded, or otherwise attached, to the
central portion of load transfer plats 86 on the side
opposite from the transfer plate tab 88. Load transfer plate
pickup 90 is used to unload the head, as explained in more
detail hereinbelow.
An unload diaphragm 94 has an outer frame 95 and an inner
frame formed by legs 96. The outer frame 95 is welded, or
otherwise attached to corresponding attachment tabs 106 on
housing 12. Tongues 97 are used to further anchor transducer
wires 53.
The inner frame legs 96 are used to secure an unload beam
9B to the outer frame US. This is effected by sliding unload
beam 98 between legs 96 and outer frame 95 and weldirlg beam
20 98 to legs 96. Unload beam 98 also has a hollow central
region into which an unload beam tab 99 projects horizontally
offset from the plane of beam 98. The unload beam tab 99 is
inserted into the region enclosed by transfer plate pick-up
90. The two ends of unload beam 98 have two offset lips 1
which pass through slots 16 in housing 12.
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Suspension diaphragm attachment tabs 10g are formed at
two diametrically opposed spots on housing wall 108. The
cutouts 68 of suspension diaphragm 60 accommodate the
vertical portions of the tabs 100, while the horizontal
portion of tabs 100 mate with corresponding regions of outer
frame 66 of suspension diaphragm 60. The unload diaphragm
attachment tabs 106 are formed by punching in diametrically
opposed portions of housing walls 108 and rim 102 to form
member 110 aligned with tabs 100. A first
horizontal surface of member 110 serves as tab 106 for
attachment to unload diaphragm 94. The load diaphragm
attachment tabs 112 are each formed by punching in a portion
of member 110 to form a second horizontal surface which mates
with a portion of the load diaphragm outer frame 80, while
the cutouts 82 of load diaphragm 76 accommodate the vertical
surface portion of tab 112. The tabs are not drawn to stale
so that they may be seen more easily. The configuration of
attachment tabs 100, 112, and 1~6 restrains the suspension
(60), load (76) and unload (94) diaphragms from lateral
motion, but allows unrestricted motion of the members
attached to their inner frames. In other words, the slider
52, suspension pickup 72, load transfer plate 86 and unload
beam 98 are free to extend and retract along a common axis
which is perpendicular to the rotating disk surface
The load diaphragm 76 forms a linear spring throughout
the operational movement range. Referring now to Figures 3
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A-D, there is shown how load diaphragm 76, as well as for the
other diaphragms, is preformed to produce a linear spring.
The material used for load diaphragm 76, as well as for the
other diaphragms, is cold rolled steel, but other suitable
materials may be used. Referring now to Figures 3 A-C, there
is shown the first step in the forming of load diaphragm 76.
The outer frame 80 is formed in four separate areas, 140,
141, 142, and 143 respectively, shown shaded for easier
identification. The four areas are along two axes, each axis
briny approximately at 30 from the axis connecting the two
cutouts 82. the inner frame 78 is formed in the two shaded
areas, 144 and 14S, also along the axis connections thought
cutouts 82. Each of the forms for the inner and outer frame
are cylindrical in profile, with the outer frame being
bent generally upwardly around the axis connecting cutouts 82
and the inner frame being bent generally downwardly around
this axis. Preferably, the forming of the two frames is
performed simultaneously between rollers which pass along
corresponding areas of each frame in a direction transverse
to the axis along which the frame is formed.
Next the load transfer plate 86 and pick-up 90 are
attached to the load diaphragm 76 (jig. ED). The resulting
load diaphragm transfer plate assembly is assembled to
housing 12 by laterally collapsing outer frame 80
sufficiently to allow its cutouts 82 to slip under the
corresponding attachment tabs 112 for attachment thereto. As
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the second step of the forming operation, the diaphragm 76 is
extended by pulling the transfer plate 86 along its trays-
verse axis until the regions of bridges 79, that is, the
junctions of the inner and outer frame, yield and those
regions bend upward, as shown by the dotted lives of Figure
ED. The solid lines of Figure ED show the diaphragm after
its release from its stretched position. This two step
forming creates an essentially cylindrical profile to each
frame when the load diaphragm 76 is in equilibrium, as
indicated by the solid lines of Fig. ED. When the diaphragm
76 is compressed, the narrow portions of the outer frame
remain curved upward, due to the angle created when each of
the bridges 79 yielded during forming. This allow sore
lateral flexibility to the outer frame, thus preventing
lo stresses that would cause non-linearities in the deflect
channeled relationship of the diaphragm 76 when operating
through its nominal plane.
Referring now to figures 4 through 6, there is shown a
cross-section of housing 12 illustrating the limits to which
the slider 52 can extend and retract. The various parts are
not drawn to scale for easier identification. Figure 4
illustrates the position of the various elements when the
slider 52 is allowed to extend fully under the influence of
the load diaphragm 76. In this vase load diaphragm 76 bows
outwardly and the loading forte is transmitted via transfer
plate tab 88 to pivot dimple 61 on suspension diaphragm 60,
which then bows out and pushes slider 52 into an extended
position. The outward motion is stopped when the dimple 92 on
the spanning member of transfer plate pick-up 90 us inter-
copied by the unload beam tab 99. Figure 5 illustrates the effect of the air bearing produced by the rotating disk. In
this case the force produced by the air pressure pushes in
slide! 52 and in turn, via load transfer plate tab 88, load
diaphragm 76. In this case, the preluded load diaphragm 76
and suspension diaphragm 60 are each pushed approximately
flat and the dimple 92 on the transfer plate pick-up 90 rides
up away from the unload beam tab 99. The transfer plate
pick-up 90 passes through the unload beam central window with
sufficient clearance to allow free and independent vertical
lo motion induced by its coupling to the slider bearing 52~ via
the load transfer plate 86 and tab 88, during dynamic opera-
lion of the head.
Referring now back to Figure 1, it can be seen that
housing 12, and the various elements contained therein, is
mounted to the votary actuator arm 20 by positioning the
housing locating surface 11 (see Figure I within a recess 23
in arm 20 and seating the housing reference lip 13 on its
corresponding surface of end portion 22 of arm 20, where it
is attached using an adhesive, or any other suitable means.
The base of load/unload leaf spring 32 is attached on one
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side of arm 20 and the cantilevered end of load/unload leaf
spring 32 is attached to the offset lips 14 on the unload
beam 98. Positioned strategically along the leaf spring 32
is a ramp 35 which intercepts a aye 40 positioned accord-
tingly. During the unload operation, the actuator arm rotates until jam I eon tats ramp 35. Continued rotation
of arm 20 pauses the leaf serving 32 to be pushed toward arm
20 pivoting at its base and so pushing the unload beau lips
14 toward arm 20~ Referring now to Figure 6 it an be seen
that this has the effect of moving the unload beam 98 toward
housing lip 13. The unload beam tab 99 interfaces with the
transfer plate pick-up dimple 92, which in turn lifts Tao
transfer plate 86, removing the force induced by load
diaphragm 76 from slider 52. The slider I is lifted from
the disk by transfer plate tab 38 interfacing with suspension
pick-up dimple 74, centrally located in the U-shaped suspend
soon pickup 72.
This ~onludes the description of the preferred
embodiment. The head module described provides a low spring
rate to the head slider in roll and pith and in the yaw axis
perpendicular to the disk surface. This allows the head
slider to maintain the orate attitude throughout its
flight, not only during normal operation, but also while
loading and unloading onto the disk surface. The particular
US arrangement of parts also provides to the head slider a high
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lateral stiffness which prevents low frequency r e s o n a n c e
problems The head mud has a relatively low mass,
approximately 0.5 gram in the embodiment described, and the
portray arrangement provides for an even lower suspended
mass.
Modifications to the preferred embodiment will also be
apparent to those skilled in the art without departing from
the spirit and scope of the present invention. Accordingly,
it is intended that this invention be not limited to the
embodiments disclosed herein except as defined by tune appended
commas.
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