Disk drive assembly station

An assembly station is provided for use in the assembly of disk drive units of the type used in microcomputers, such as personal computers and the like. The assembly station comprises a main platform having a head fixture and a disk fixture for respectively receiving and supporting a head actuator subassembly and a disk subassembly of a disk drive unit. The disk fixture supports the disk subassembly for sliding displacement into precision registry with the actuator subassembly to accommodate facilitated mounting of a housing base onto the actuator and disk subassemblies. In the preferred form of the invention, the assembly station is further adapted to receive and support additional disk drive components for mounting within the housing base. The platform is adapted for inversion to expose these additional disk drive components through platform openings for relatively simple attachment to the housing base at predetermined positions. Moreover, the head and disk fixtures are adapted to support the partially assembled disk drive unit in a manner permitting operational component testing prior to removal from the assembly station.

BACKGROUND OF THE INVENTION 
This invention relates generally to apparatus and methods for facilitated 
assembly of disk drive units of the general type used in microcomputers, 
such as personal computers and the like. More particularly, this invention 
relates to an assembly station adapted for relatively rapid precision 
assembly of disk drive units. 
In recent years, microcomputer equipment particularly such as personal and 
desktop computers have become extremely popular for a wide variety of 
business and educational and other uses. Such computers commonly include a 
main central processor unit having one or more memory storage disks for 
storage of data. In one popular form, the storage disk or disks are 
provided as part of a Winchester-type disk drive unit having multiple 
storage disks supported in a stack on a rotary spindle within a 
substantially sealed disk drive housing. The stacked disks are rotatably 
driven in unison by a small spindle motor, and one or more electromagnetic 
heads are displaced by a head actuator assembly to traverse disk surfaces 
for purposes of reading and writing data. Such Winchester-type disk drive 
units, sometimes referred to as "hard" disks, are generally preferred in 
comparison to so-called floppy disk drives due to their higher memory 
storage capacities and faster operating speeds. 
The expanding popularity of personal and desktop computers has been 
accompanied by a demand for Winchester-type disk drive units having 
increased memory storage capacities with rapid read/write performance 
characteristics. Moreover, a significant market demand has arisen for 
smaller disk drive units possessing increased memory storage capacities. 
As a result, modern disk drive units have become increasingly complex and 
commonly include multiple storage disks in combination with multiple 
read/write heads which are mounted within a highly compact disk drive 
housing. To achieve the desired performance characteristics, such disk 
drive units have unfortunately required extreme precision during assembly 
stages during which individual disk drive components or subassemblies are 
typically installed one at a time into an open housing member or base. In 
the past, such precision component assembly has been obtained through the 
use of substantial manual labor in a manner requiring a high degree of 
skill and care, thereby inherently limiting production efficiency. 
Moreover, manual assembly of disk drive components can be a particularly 
difficult and tedious process, such as the assembly of a multiple disk 
stack into precision registry with multiple read/write heads of a head 
actuator assembly. 
There exists, therefore, a significant need for improved devices and 
methods for assembling computer disk drive units and the like, 
particularly with respect to precision assembly of stacked memory storage 
disks into registration with a plurality of read/write heads. The present 
invention fulfills these needs and provides further related advantages. 
SUMMARY OF THE INVENTION 
In accordance with the invention, a disk drive assembly station and related 
assembly methods are provided for quickly and easily assembling components 
of a disk drive unit in a precision manner. The assembly station includes, 
in general terms, a main platform having separate head and disk fixtures 
in a predetermined, precision spaced relation for respectively receiving 
and supporting a head actuator subassembly and a disk subassembly of a 
computer disk drive unit. The head and disk fixtures support the 
subassemblies for movement into precision registration with each other, 
and for simplified mounting of the subassemblies into a housing base 
forming a portion of a sealed housing for the disk drive unit. 
In the preferred form of the invention, the head and disk fixtures define 
reference surfaces for respectively receiving and supporting the actuator 
subassembly and the disk subassembly on the main platform. Torque spindles 
are provided with both fixtures for secure fastening to the head actuator 
and disk subassemblies, respectively, in a manner drawing the 
subassemblies into firmly seated relation with the reference surfaces. A 
transfer tool is conveniently provided for facilitating manual or 
automated handling of the disk subassembly for precision placement onto 
the disk fixture, wherein the disk subassembly typically comprises a 
plurality of memory storage disks arranged in a stack. The transfer tool 
is designed to prevent disk damage or contamination by guarding against 
disk surface contact with foreign objects. 
The disk fixture is supported on the platform by a bearing unit which 
accommodates disk fixture displacement in a direction toward or away from 
the head fixture. A preferred bearing assembly comprises linear bearings 
which support the disk fixture for substantially straight-line 
displacement toward and away from the head fixture. A push bar carried by 
the disk fixture is operable to translate the disk fixture along the 
platform between a first position spaced substantially from the head 
fixture, and a second position for supporting a disk subassembly in 
precision registration with a plurality of read/write heads of the 
actuator subassembly supported on the head fixture. Stop members located 
respectively on the disk fixture and the main platform are engageable to 
define a precise stopping point when the disk fixture is displaced to the 
second position. 
The actuator subassembly is mounted onto the head fixture together with a 
shipping comb for maintaining the plurality of read/write heads in spaced 
relation to each other. A loading comb is carried by a comb support arm 
mounted pivotally on the platform for swinging movement into registration 
with the actuator subassembly. The loading comb includes tapered comb 
teeth for maintaining the read/write heads in spaced relation while 
separating a shipping comb from the actuator subassembly to permit 
shipping comb removal. The loading comb maintains the read/write heads in 
spaced relation as the disk fixture is translated along the platform to 
move the disk subassembly into registration with the actuator subassembly. 
When such registration is achieved, the loading comb is retracted from the 
subassemblies such that the tapered comb teeth gradually release the 
read/write heads to land gently within outer landing zones on the surfaces 
of the memory storage disks. 
A housing base is installed quickly and easily over the actuator and disk 
subassemblies and appropriately fixed thereto by suitable fasteners. 
Housing pins upstanding from the platform are provided for reception 
through preformed ports in the housing base to pre-align the housing base 
with the underlying subassemblies. The housing pins guide the housing base 
through a sliding downward movement into precision engagement with the 
subassemblies for simple connection thereto. One or more of these housing 
pins may be carried on the platform by a pivoting swing arm for movement 
to an out-of-the-way position until housing base installation is desired. 
Prior to housing base installation, additional components of the disk drive 
unit are advantageously installed onto the platform at predetermined 
locations. The components may include, for example, a solenoid unit and a 
magnet unit for operative interaction with the actuator subassembly during 
normal operation of the disk drive unit. Subsequent to housing base 
installation, the entire platform is inverted to expose selected interior 
regions of the now-underlying housing base through platform openings. 
Appropriate fasteners are insertable through these platform openings for 
securely fixing the disk drive components to the housing base. 
With the platform in an inverted orientation, the actuator and disk 
subassemblies may be coupled to test means for rotatably driving the 
memory storage disks in operative relation with the actuator subassembly. 
In the preferred form, such rotatable driving of the disks causes the 
read/write heads to fly in slight spaced relation with respect to the 
outer landing zones on the associated disk surfaces. During this mode, the 
actuator subassembly is manually displaced to shift the read/write heads 
into alignment with and conventional parking at inner landing zones on the 
associated disk surfaces. The solenoid unit may be adjusted as required to 
lock or park the heads at the inner landing zones. The platform is then 
returned to the original upright orientation, whereupon the torque 
spindles are released from the associated actuator and disk subassemblies 
to permit removal of the partially assembled disk drive unit from the 
assembly station. Such removal is achieved quickly and easily by lifting 
the housing base upwardly in guided relation with the housing pins to 
insure straight lift-off of the subassemblies from the platform. 
Importantly, the partially assembled disk drive unit includes the actuator 
and disk subassemblies mounted in precision registration within the 
housing base. 
Other features and advantages of the invention will become more apparent 
from the following detailed description, taken in conjunction with the 
accompanying drawings which illustrate, by way of example, the principles 
of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in the exemplary drawings, a disk drive assembly station referred 
to generally in FIGS. 1-3 by the reference numeral 10 is provided for 
facilitating precision assembly of key components of a disk drive unit of 
the type used in modern microcomputers, such as personal and desktop 
computers and the like. The disk assembly station 10 includes a head 
fixture 12 for precision support of a head actuator subassembly 14, as 
depicted in FIGS. 2 and 3. In addition, the station 10 includes a movable 
disk fixture 16 for supporting a disk subassembly 18 (FIG. 2) which may 
include multiple memory storage disks 20 arranged in a vertical stack 
(FIG. 10). The disk fixture 16 accommodates displacement of the supported 
disk subassembly 18 into precision positional registry with the actuator 
subassembly 14 (FIG. 13) to facilitate subsequent mounting of both 
subassemblies 14 and 18 within a housing base 22 (FIG. 3) of a computer 
disk drive unit. 
The disk drive assembly station 10 of the present invention advantageously 
provides a relatively compact and easily manipulated apparatus and method 
for quickly and easily assembling key or precision components of a 
computer disk drive unit or the like. The assembly station 10 includes 
appropriate support members at predetermined and precision spaced 
locations for securely and safely supporting disk drive components for 
facilitated assembly. More specifically, a variety of disk drive 
components can be placed accurately and safely onto the head and disk 
fixtures 12 and 16 to orient those components in fixed predetermined 
relation to each other. The fixtures maintain the disk drive components in 
the desired positions during mounting of the housing base 22 which 
comprises a portion of a conventional, substantially sealed housing for 
the disk drive unit. Most importantly, the actuator subassembly 14 and the 
disk subassembly 18 are securely retained in a precision registration 
during mounting of the housing base such that substantially optimized 
cooperative interaction between these subassemblies may be achieved during 
operation of the disk drive unit in the course of storing and/or 
retrieving data. 
Although a fully assembled disk drive unit is not shown in detail in the 
accompanying drawings, the assembly station 10 is particularly designed 
for use with disk drive units having the plurality of memory storage disks 
20 arranged in a common stack to define the disk subassembly 18. More 
particularly, as shown best in FIG. 14, the disk subassembly 18 comprises 
a central cylindrical hub 24 encasing a built-in spindle drive motor 
having an axially elongated stator shaft 26. During disk drive operation, 
the stator shaft 26 is securely anchored by mounting, for example, of its 
opposite ends to components of the disk drive housing (not shown in FIG. 
14) and electrical power is appropriately coupled to the spindle motor via 
plural leads 27 projecting from one end of the stator shaft 26. During 
spindle motor operation, the hub 24 is rotatably driven at a selected 
speed, typically about 3600 rpm, to correspondingly rotatably drive the 
hub 24 and the supported stacked plurality of the memory storage disks 20 
in unison. Spacer rings 28 are interposed between the storage disks 20 to 
permit the upper and lower disk surfaces to be accessed by appropriate 
servo and/or read/write heads, as will be described in more detail. Any 
number of memory storage disks may be used, with FIG. 14 depicting five 
disks 20 arranged in a coaxial stack. Further details regarding a 
preferred disk subassembly and a related spindle drive motor may be found 
by reference to copending U.S. application Ser. No. 173,619, entitled DISK 
DRIVE SPINDLE MOTOR, which is incorporated by reference herein. 
The head actuator subassembly 14 comprises another key component of the 
disk drive unit. An exemplary actuator subassembly 14 is shown in the 
accompanying drawings in conjunction with the disk drive assembly station 
10. As best depicted in FIG. 7, the illustrative actuator subassembly 14 
comprises a cast or machined casing 30 supported for rotation by means of 
an appropriate bearing (not shown) about a central support shaft 31. At 
least one and preferably both ends of the support shaft 31 are adapted for 
connection to the disk drive housing to orient the casing 30 for rotation 
about an axis generally parallel to the stator shaft 26 of the associated 
disk subassembly 18. The actuator casing 30 includes a plurality of 
relatively stiff arms 32 which radiate outwardly along a common azimuth 
and are secured by stake rings 33 or the like to a corresponding plurality 
of flexure arms 34. These flexure arms 34 in turn support electromagnetic 
read/write heads 35 or the like. As is known in the art, during operation 
of a disk drive unit, the heads 35 are positioned respectively in close 
proximity with individual surfaces of the associated memory storage disks 
20 for purposes of reading and/or writing data. In the illustrative 
drawings, a total of six casing arms 32 are shown, with the upper and 
lower casing arms carrying single flexure arms 34 and associated heads 35 
for respective association with the uppermost and lowermost storage disk 
surfaces of the subassembly 18. The remaining casing arms 32 each carry a 
pair of the flexure arms 34 which support read/write heads 35 oriented in 
opposite-facing directions for association respectively with the 
immediately overlying and underlying storage disk surfaces. When supported 
in registry with the disk subassembly 18, the read/write heads 35 are thus 
interleaved into the spaces between the storage disks 20 (FIG. 11), with 
the heads 35 disposed in individual read/write association with the 
storage disk surfaces. Further details regarding a preferred actuator 
subassembly 14 may be found by reference to copending application Ser. No. 
173,618, entitled ACTUATOR ASSEMBLY FOR HARD DISK DRIVES, which is 
incorporated by reference herein. 
The actuator subassembly 14 further includes means for controllably 
displacing the heads 35 through radial traverses relative to the storage 
disks 20 of the disk subassembly 18. While the particular mechanisms and 
methods used to obtain such displacement may vary, the accompanying 
drawings illustrate a movable coil dc motor having a bobbin or coil 36 
carried by the actuator casing 30. The bobbin coil 36 is supported, during 
normal disk drive operation, in magnetically coupled association with 
permanent magnets 37 (FIG. 7) mounted within a housing 38 of a magnet unit 
39. A solenoid unit 40 (FIG. 2) is also included as part of the actuator 
subassembly and includes a flex cable 41 for appropriately coupling 
signals from a system controller (not shown) to the bobbin coil 36 (FIG. 
7) in a manner causing the coil to displace through an arcuate path in 
magnetic coupled relation with the permanent magnets 37 (FIG. 7). Such 
displacement effectively translates the read/write heads 35 through radial 
traverses relative to the associated disks 20. In addition, as known in 
the art, the flex cable 41 couples appropriate read/write signals to or 
from the plurality of heads 35. In this regard, the flex cable is shown to 
include an inboard connector fitting 41, anchored to a suitable location 
on the solenoid unit 40, and an outboard connector fitting 41" for 
appropriate coupling to the system controller at a position outside the 
housing of the disk drive unit. 
The disk drive assembly station 10 of the present invention is particularly 
designed for facilitated and precision assembly of all the above-described 
disk drive components into the housing base 22 (FIG. 3). The assembly 
station supports the various components in predetermined, precision 
positions to accommodate simplified housing base affixation without 
requiring positional adjustment of components during or after assembly. 
The relative dimensions are fixed by the assembly station 10. Moreover, 
the assembly station 10 is adapted for facilitated manual assembly of the 
disk drive components, or for integration into an appropriate automated 
assembly process. 
With reference to FIGS. 1-6, the disk drive assembly station 10 comprises a 
generally horizontally oriented platform 42 supported between left and 
right support standards 44. These support standards are adapted in turn 
for appropriate connection to an underlying support frame or base 45 which 
is suitably anchored in a stationary position. The platform 42 is 
supported from the standards 44 by a pair of coaxially aligned journal 
pins 46 (FIGS. 5 and 6) which are secured to the underside of the platform 
by clamp units 43 and project outwardly for reception into rotatable 
bearings 47 on the support standards 44. A lock lever 48 has an inboard 
end pivotally mounted to the underside of the platform 42 by a pin 49 
(FIG. 19), and a spring 50 reacts between the lever 48 and the platform 42 
to swing the lever 48 in a direction seating a lever tooth 51 normally 
into a notched seat 52 (FIG. 4) formed in a lock bracket 53 mounted on the 
adjacent support standard 44. The lock lever 48 may be withdrawn manually 
from the bracket seat 52 to permit platform rotation about the axis of the 
journal pins 46, thereby permitting platform inversion and corresponding 
reception of the lever tooth 51 into a notched seat in a second bracket 54 
on the standard, as viewed in dotted lines in FIG. 4. Inversion of the 
platform 42 is performed during a latter stage of assembly of the disk 
drive unit, as will be described in more detail. 
The head fixture 12 comprises a plurality of relatively small support 
members mounted on the platform 42 and cooperatively defining a series of 
upwardly presented surfaces for seated support of the actuator subassembly 
-4 and related components. For convenience and ease of description, these 
support members will be collectively referred to herein as a baseplate 
identified by the reference numeral 56. More specifically, with reference 
to FIGS. 1, 2 and 7-9, this baseplate 56 is suitably mounted by screws or 
the like onto the platform 42 at a position disposed generally along one 
side margin of a platform opening 57. An upright, generally cylindrical 
support sleeve 60 extends perpendicularly through the platform 42 and the 
baseplate 56 to define an upwardly presented annular reference surface 61 
(FIG. 8). The support sleeve 60 is firmly engaged by a clamp unit 62 
attached to the underside of the platform 42, as viewed in FIG. 9, wherein 
this clamp unit is appropriately adjusted to insure precision placement of 
the reference surface 61 in accordance with the desired geometry of the 
assembled disk drive unit. A key 63 may also be provided within aligned 
keyways on the support sleeve 60 and the platform 42 to positively lock 
the support sleeve 60 against rotation relative to the platform. 
An elongated torque spindle 64 extends coaxially through the support sleeve 
60 for use in attachment of the actuator subassembly 14 to the head 
fixture 12. As shown in FIGS. 7-9, this torque spindle 64 comprises an 
elongated shaft rotatably received through a bore formed in the support 
sleeve. A lower end 64' of the torque spindle 64 is threaded for screw-on 
attachment of an enlarged head 66 which conveniently includes external 
knurling or the like for easy manual grasping and rotation. A compression 
spring 67 reacts between a washer 68 at the lower end of the support 
sleeve 60 and an upwardly presented shoulder on the head 66 to urge the 
entire torque spindle 64 downwardly within the support sleeve 60. A raised 
spool 69 or the like on the torque spindle 64 is engageable with a stop 
key 70 extending transversely through the support sleeve 60 to define a 
lower end limit to torque spindle motion. 
The upper end of the torque spindle 64 is shaped to define a cylindrical 
land 71 (FIG. 8) of reduced diametric size. The land 71 projects upwardly 
a short increment above the adjacent reference surface 61 on the support 
sleeve 60. The upper extent of the land 71 joins with a threaded upper tip 
72 for threaded attachment to the actuator subassembly. Such threaded 
attachment is achieved by engaging the tip 72 into a threaded bore 73 at 
one end of the support shaft 31 of the actuator subassembly 14. In this 
regard, in the preferred form of the invention, this threaded bore 73 is 
formed in the upper end of the support shaft 31, whereby the actuator 
subassembly is installed onto the head fixture 12 in an inverted 
orientation, as viewed in FIG. 7. Rotation of the torque spindle 64 is 
obtained easily by grasping and rotating the spindle head 66 at a position 
below the platform 42 to draw and seat the axially uppermost end of the 
support shaft 31 firmly onto the reference surface 61 at the upper end of 
the support sleeve 60. When the tip 72 is threaded into the shaft bore 73 
with a predetermined torque load, the compression spring 67 permits 
override rotation of the head 66 relative to the spindle 64 to prevent 
overtightening. 
A spring loaded alignment pin 76 is also provided for registration with the 
actuator subassembly 14 to insure precise initial placement of said 
subassembly 14 onto the head fixture 12. More specifically, as shown best 
in FIGS. 7 and 9, the alignment pin 76 is carried for axial sliding 
movement within a guide sleeve 77 which extends generally perpendicularly 
through the platform 42 at a position closely adjacent to the support 
sleeve 60. This guide sleeve 77 is suitably mounted onto the platform to 
extend generally perpendicularly therethrough by means of a clamp unit 78 
or the like fastened onto the underside of the platform. A key 79 may also 
be provided to prevent relative rotation of the guide sleeve with respect 
to the platform 42. 
The alignment pin 76 protrudes upwardly through the baseplate 56 and 
terminates in a tapered upper tip 80 for reception into a port defined, 
for example, by the stake ring 33 anchoring the adjacent upper flexure arm 
34 of the subassembly 14. The tip 80 is spring biased for normal reception 
into the stake ring port by means of a lower compression spring 82 
reacting between a stop ring 83 on the pin 76 and an inboard surface of a 
sleeve cap 84 mounted onto the lower of the guide sleeve 77. A head 85 is 
secured onto the exposed lower end of the alignment pin 76 in a position 
for easy manual grasping below the platform to withdraw the pin tip 80 
from the adjacent stake ring port. However, when the head 85 is released, 
the spring 82 urges the alignment pin 76 to translate upwardly within the 
guide sleeve 77, thereby displacing the tapered tip 80 into the stake ring 
port. As a result, the alignment pin 76 cooperates with the torque spindle 
64 for normally locking the inverted actuator subassembly 14 in position 
on the head fixture 12. 
The stake rings 33 on the plurality of actuator arms 32 conventionally 
define a vertically aligned series of stake ring ports. These stake rings 
33 provide a convenient mounting structure for a shipping comb 86 having a 
plurality of spaced teeth 87. The comb teeth 87 are interposed between the 
multiple flexure arms 34 to maintain the read/write heads 35 in spaced 
relation during manufacturing and/or shipping processes. The shipping comb 
86 is shown best in FIGS. 2 and 7, and is normally secured in a releasable 
manner to the actuator subassembly 14 by means of a short mounting post 88 
received through the ports in two or more of the stake rings 33. 
Importantly, as viewed in FIG. 7, the mounting post 88 is received through 
the stake rings located generally opposite the alignment pin 76 when the 
subassembly 14 is installed onto the head fixture 12. With this 
arrangement, the head actuator subassembly 14 can be installed onto the 
disk assembly station 10 without requiring prior removal of the shipping 
comb 86. 
The shipping comb 86 is removable quickly and easily from the actuator 
subassembly 14 subsequent to subassembly mounting onto the head fixture 
12. More particularly, as shown in FIGS. 1, 2, 10 and 13, a loading comb 
90 includes a plurality of comb teeth 92 disposed in a vertical spaced 
array at the distal end of a comb pivot arm 93. This pivot arm 93 is 
pivotally mounted b a pin 94 to the main platform 42 in a manner 
accommodating swinging movement of the loading comb 90 into or away from 
registration with the actuator subassembly 14 on the head fixture 12. When 
the actuator subassembly 14 is secured onto the head fixture 12, the comb 
pivot arm 93 is rested at an out-of-the-way position, as viewed in solid 
lines in FIG. 2, to space the loading comb teeth 92 a substantial distance 
from the subassembly 14. A limit post 95 on the platform 42 conveniently 
provides a stop engaging the comb arm 93 in this out-of-the-way position. 
An over-center spring 96 (FIGS. 1 and 19) secured between the platform 42 
and the comb arm 93 effectively retains the arms 93 against the limit post 
95. 
However, subsequent to subassembly mounting onto the head fixture 12, the 
comb pivot arm 93 is pivoted to displace the comb teeth 92 toward the 
flexure arms 34 of the actuator subassembly 14. As shown in FIG. 10, the 
leading edges of the comb teeth 92 are appropriately tapered to fit 
smoothly into the spaces between the flexure arms 34 in a manner retaining 
the operating surfaces of the read/write heads 35 against contact with 
each other. Further advancement of the comb teeth 92 (shown in dotted 
lines in FIG. 2) effectively releases the teeth 87 of the shipping comb 
86. This permits relatively easy shipping comb removal by simple pivoting 
of the comb teeth 87 away from the heads 35 and appropriate lifting of the 
comb post 88 from the stake rings 33. The removed shipping comb 86 may be 
discarded, or reused, as desired. A second limit post 97 on the platform 
42 prevent overtravel of the loading comb pivot arm (FIG. 2). Moreover, as 
shown in FIGS. 1 and 19, a dashpot assembly 91 is conveniently mounted to 
the underside of the platform 42 and has a ram 91' coupled through a link 
91" to the comb pivot arm 93 to insure gentle swinging movement of the 
pivot arm in either direction relative to the head fixture 12. 
Additional disk drive unit components are also installed at the rear of the 
actuator assembly 14, as viewed in FIGS. 2, 7, 13 and 17 to position the 
magnets 37 (FIG. 7) in operative relation with the bobbin coil 36. In this 
regard, for secure and precise support of the magnet unit 39, the fixture 
baseplate 56 includes a pair of upstanding locator pins 98 (FIG. 20) 
positioned adjacent to the casing 30 of a supported actuator subassembly 
14. In addition, a pivot link 99 (FIGS. 20, 22 and 23) mounted swingably 
to the baseplate 56 includes an upstanding post 100 for reception into a 
port 101 in the magnet housing 38 to support the magnet unit 39 in 
registry with the bobbin coil 36 (FIG. 7). As viewed in FIGS. 20, 22 and 
23, this pivot link 99 is normally locked an an out-of-the-way position 
(dotted lines in FIG. 20) by means of a retainer pin 102 (FIG. 22) urged 
by a spring unit 103 into a slot 102' in the baseplate. However, with the 
magnet unit 39 seated against the locator pins 98, the retainer pin 102 
can be retracted from the slot 102' to permit pivot link rotation to a 
secondary position with the post 100 aligned for reception into the magnet 
housing port 101 (FIG. 7) (solid lines in FIG. 20). In this secondary 
position, the pivot link 99 is released whereupon the spring unit 103 
urges the post 100 into the housing port 101 (FIG. 7) to hold the magnet 
unit 39 in place. A second slot in the baseplate receives the retainer pin 
102 to releasably lock the pivot link 99 and the supported magnet housing 
in place. 
The actuator subassembly 14 additionally includes the solenoid coil 40 with 
associated flex cable 41 and a solenoid latch mechanism 104. These 
components are coupled generally to one side of the actuator casing 30, as 
viewed in FIGS. 2, 13, 17, 20 and 21. A solenoid support bracket 105 
projects laterally from one side of the baseplate 56 in generally 
cantilevered relation over the platform opening 57. This support bracket 
105 is geometrically shaped for rested, seated support of the solenoid 
latch mechanism 104 and the associated flex cable 41, with the flex cable 
folded in a direction generally away from the head fixture 12 (FIG. 2). As 
shown best in FIGS. 13, 17, 20 and 21, the solenoid support bracket 105 
(FIGS. 20 and 21) is beneficially mounted to the platform 42 by a pivot 
pin 106 or the like for initially supporting the solenoid unit 40 in a 
position pivoted away from the actuator subassembly (FIGS. 1 and 13). 
However, immediately prior to installation of the housing base 22 (FIG. 3) 
the solenoid bracket 105 is pivoted in a direction swinging the solenoid 
unit 40 toward the subassembly 14 (FIGS. 17, 20 and 21) for fastening into 
the housing base 22, as will be described. 
The disk fixture 16 includes a separate baseplate 110 adapted to receive 
and support the disk subassembly 18. Importantly, this baseplate 110 is 
movably mounted with respect to the platform 42. With this construction, 
the disk subassembly 18 can be installed onto the baseplate 110 in an 
initial position spaced sufficiently from the head fixture 12 to prevent 
accidental contact of the subassemblies with each other. However, while 
the flexure arms 34 of the actuator subassembly 14 are appropriately held 
in spread relation by the loading comb 90, the disk fixture 16 including 
the baseplate 110 is movable quickly and easily to displace a supported 
disk subassembly 18 into precision registration with the multiple 
read/write heads 35 of the actuator subassembly 14. 
More specifically, with reference to FIGS. 1-3 and 11-17, the baseplate 110 
is supported by a plurality of three or more linear bearing units 112 
(FIGS. 1 and 11) for substantially straight-line sliding displacement 
along a pair of parallel guide rails 114 mounted securely upon the 
platform 42. As shown in FIGS. 11 and 14, the baseplate 110 is supported 
over an elongated opening 115 in the platform 42. As upright support 
sleeve 116 is secured to the baseplate 110 by means of a clamp unit 118 or 
the like to extend generally perpendicularly through the platform opening 
115 and the baseplate 110. A key 117 may also be provided to lock the 
support sleeve 116 against rotation with respect to the baseplate 110. The 
support sleeve 116 defines an upwardly presented annular reference surface 
120 (FIGS. 11 and 15) which surrounds an elongated torque spindle 122 
passing coaxially through the support sleeve 116. The upper end of the 
torque spindle 122 defines a tapered truncated conical seat 123 (FIG. 15) 
of relatively fine tolerance dimensions and which blends into an upwardly 
projecting threaded tip 124. The geometry of the conical seat 123 and the 
threaded tip 124 are adapted for precision threading advancement into a 
tapered entrance 125 leading to a threaded bore 126 formed in the stator 
shaft 26 of a disk subassembly 18. 
When the disk subassembly 18, including the stacked array of memory storage 
disks 20, is mounted onto the disk fixture 16, the disk subassembly 18 is 
oriented in an inverted position for thread-in advancement of the torque 
spindle tip 124 into the upper end of the stator shaft 26. Such threaded 
advancement is achieved by grasping and rotating an enlarged head 128 
threaded onto a threaded lower end of the torque spindle 122 (FIG. 14) at 
a position below the platform. A compression spring 130 reacts between a 
washer 131 seated against the lower end of the support sleeve 116, and an 
upper shoulder on the head 128 to urge the torque spindle downwardly 
within the support sleeve 116 with a predetermined spring force. An 
enlarged spool 132 on the torque spindle 122 is engageable with a stop key 
133 inserted through the support sleeve 116 to provide a downward end 
limit stop to torque spindle motion within the support sleeve. 
Accordingly, threaded advancement of the tip 124 into the stator shaft 26 
draws the end of the stator shaft into seated relation with the reference 
surface 120 with a limited force controlled by the design characteristics 
of the spring 130. When that force is achieved, further rotation of the 
head 128 overrides relative to the torque spindle 122. Importantly, when 
the disk subassembly 18 is seated onto the reference surface 120, a 
precision positional relationship between the actuator and disk 
subassemblies is obtained. 
A transfer tool 140 may be provided for facilitated handling of the disk 
subassembly 18 during mounting thereof onto the disk fixture 16. The 
transfer tool 140, shown best in FIGS. 2, 11 and 12, comprises an 
elongated and relatively rigid tool body 142 having a split clamp head 144 
at one end thereof. A clamp screw 146 extends through an elongated smooth 
bore 147 in the tool body to bridge the split in the clamp head 144 and 
for threading into a threaded bore 148 (FIG. 11). When the clamp screw 146 
is advanced into the threaded bore 148, a head 150 on the screw bindingly 
engages a rear tool face to cause a pair of facing stops 151 at the clamp 
head split to be drawn into abutting engagement with each other (FIG. 2). 
When the stops 151 are engaged, an interior surface 152 of the clamp head 
144 bindingly engages a relatively rigid structural peripheral portion of 
the hub 24 of the disk subassembly 18 for securely holding the subassembly 
without the use of direct manual assistance. With this transfer tool 140, 
the disk subassembly 18 can be handled and transferred manually or with 
automated equipment for rapid and accurate placement onto the disk fixture 
16 in an inverted position. 
A tool support stand 154 is mounted on the platform 42 for receiving the 
transfer tool 140 having a disk subassembly 18 loaded therein. As viewed 
in FIGS. 1, 11 and 12, the tool stand 154 includes a pair of upstanding 
guide posts 155 and 156 projecting upwardly from the platform 42 to extend 
slidably through bearings 157 (FIG. 12) carried by an upper plate 158. A 
dashpot unit 160 on the platform 42 has a spring loaded ram 162 for urging 
the plate 158 to a position near the upper ends of the posts 155 and 156, 
and a clamp unit 164 or the like is fastened onto the upper end of the 
post 155 to prevent plate removal therefrom. An upper face on the plate 
158 defines a relatively flat support surface for rested reception of the 
transfer tool 140. Guide pins 166 project upwardly from the plate 158 
through aligned ports in the transfer tool body such that a disk 
subassembly 18 carried by the transfer tool is disposed in alignment over 
the torque spindle 122 of the disk fixture 16. Threaded advancement of the 
spindle tip 124 draws the disk stack firmly onto the reference surface 
120, as previously described, with such draw-down motion being resisted by 
the support stand dashpot unit 160 to insure smooth motion without jarring 
or jolting which could otherwise damage the fragile disk subassembly. 
As shown in FIGS. 1, 2, 13 and 14, the disk subassembly 18 is mounted onto 
the disk fixture 16 while the fixture is positioned in significantly 
spaced relation from the head fixture 12. A push bar 170 is connected by a 
pivot pin 171 to an outboard side edge of the baseplate 110 and projects 
outwardly therefrom in a direction generally away from the head fixture 
12. This push bar 170, as viewed best in FIGS. 3 and 14, includes an 
upstanding handle 172 for easy manual grasping to displace the entire 
fixture 16 along the guide rails 114 toward and away from the head fixture 
12. In an initial position, as viewed in dotted lines in FIG. 14, a 
depending lock tab 174 on the push bar 170 seats against an outboard side 
face 175 of a raised stop member 176 mounted on the platform 42. 
However, subsequent to securement of the disk subassembly 18 onto the disk 
fixture 16, the push bar 170 is pivoted upwardly from the dotted line 
position (FIG. 14) and used as a push handle for displacing the disk 
fixture 16 along the guide rails 114 in a direction toward the actuator 
subassembly 14 on the head fixture 12. A pair of hardened stops 178 and 
180 such as the heads of a pair of screws on the baseplate 110 and on a 
stop plate 182, respectively, are engageable to define a precision stop 
point for the disk fixture 16 to orient the disk subassembly in precision 
registration with the actuator subassembly. In this position, the memory 
storage disks 20 of the disk subassembly 18 are disposed in predetermined 
and interleaved registry with the read/write heads 35, as shown in FIG. 
10. When this position is reached, the push bar 170 is pivoted downwardly 
toward the solid line position viewed in FIG. 14 to seat the stop tab 174 
engaged in front of a spring loaded lock button unit 184 mounted on the 
platform. This lock button unit 184 beneficially retains the disk fixture 
16 in a position with the stops 178 and 180 securely engaged to maintain 
the disk and head subassemblies in precision registration seated 
respectively on the head and disk fixtures. 
With the actuator and disk subassemblies 14 and 18 in registered relation, 
the loading comb 90 (FIG. 10) is retracted from the flexure arms 34. Such 
retraction is obtained by swinging the comb arm 93 away from the actuator 
subassembly to release the flexure arms 34 gradually due to the tapered 
geometry of the tips of the comb teeth 92. As a result, the read/write 
heads 35 land gently upon outer landing zones of their respective disk 
surfaces with a predetermined preload in accordance with the spring 
characteristics of the flexure arms. An upstanding housing 186 (FIG. 3) is 
conveniently provided on the platform 42 to at least partially shelter the 
loading comb 90 when retracted from the actuator subassembly. 
In addition, subsequent to movement of the disk subassembly 18 into 
registration with the actuator subassembly 14, the solenoid bracket 105 is 
movable to displace the solenoid unit 40 into a desired mounting position 
relative to the actuator subassembly. More particularly, as shown in FIGS. 
17, 20 and 21, the solenoid bracket 105 is pivotally movable about the 
pivot pin 106 to displace the solenoid latch mechanism 104 to a position 
in close proximity with the actuator casing 30. In this regard, as viewed 
in FIG. 21, the bracket 106 includes a spring loaded bracket arm 105, 
having a contoured seat 107 for cradled support of the latch mechanism 
104. 
The housing base 22 is then installed quickly and easily onto the 
above-described components of the disk drive unit for secure connection 
thereto. More particularly, the housing base 22 comprises a contoured 
housing component having at least two alignment ports 190 for receiving 
upstanding cover pins 191 and 192 which guide the base 22 into the desired 
positional registry with the underlying subassemblies. One of these ports 
190 in the housing base 22 is adapted to receive the upwardly projecting 
cover pin 191 which is supported in a fixed position at one side of the 
platform 42. The second cover pin 192 is conveniently carried by a spring 
loaded swing arm 193 for swinging displacement relative to the platform. 
This second pin 192 and the related swing arm 193 are shown in detail in 
FIG. 18, with an over-center spring 194 controlling swing arm displacement 
between first and second positions. In a first position, as viewed in 
FIGS. 1, 2 and 13, the cover pin 192 is in an out-of-the-way position to 
avoid interference With assembly of other components. However, when 
housing base installation is desired, the swing arm 193 is displaced to 
the second position (FIGS. 3 and 17) and retained thereat by the spring 
194. A pair of stop posts 195 and 196 conveniently define the termination 
points for the two positions of swing arm displacement. Moreover, the 
swing arm 193 conveniently includes a side abutment 193' to block motion 
of the comb support arm 93 toward the actuator subassembly 14 when the 
cover pin 192 is in the second position for engaging the housing base 22. 
With the cover pin 192 moved to its second position near the actuator 
subassembly 14, the housing base 22 is placed onto the underlying disk 
drive components by sliding the housing base downwardly with the pins 191 
and 192 received into the ports 190. Importantly, the cover pins 191 and 
192 have sufficient height to insure proper reception through the ports 
190 prior to contact by the housing base 22 with either subassembly 14 or 
18. Such arrangement advantageously insures proper alignment among the 
components before physical contact therebetween. Moreover, for facilitated 
assembly, the spindle leads 27 projecting upwardly from the disk drive 
spindle motor are advantageously gathered within a short straw 197 (FIGS. 
3 and 14) for easy passage through an aligned opening 198 in the housing 
base. When the housing base 22 is properly seated upon the underlying 
components, appropriate nuts and/or screws are used for securely fastening 
the housing base to the actuator subassembly 14 and to the disk 
subassembly 18, respectively. 
Subsequent to installation of the housing base 22, the straw 197 is removed 
from the spindle leads 27 to permit the leads to be appropriately coupled 
by soldering or the like to a flex cable segment 27' or the like adapted 
for connection to power supply components of a fully assembled disk drive 
unit. In addition, a clamp arm 200 may be displaced into supporting 
engagement with the housing base 22, as viewed best in FIGS. 3 and 11. 
This clamp arm 200 comprises a crank pivotally mounted onto the platform 
42 and biased by an over-center spring 202 (FIG. 2) for movement between 
two different positions. In a first position, as shown in FIG. 11, a clamp 
foot 204 is spaced above the various components being assembled on the 
platform fixtures. However, after installation of the housing base 22, the 
clamp foot 204 can be descended to engage an upwardly presented surface of 
the housing base 22 to assist in holding the partially assembled disk 
drive components on the assembly station, as shown in FIG. 3. 
In the partially assembled stage shown in FIG. 3, the platform 42 is 
rotated to an inverted position to facilitate final assembly of the 
various components to the housing base 22. More specifically, the lock 
lever 48 is released from the adjacent lock bracket 53 to permit platform 
inversion by rotation about the axis of the journal pins 46 (FIG. 4). In 
the inverted position, the tooth 51 on the lock lever 48 is engaged with 
the second lock bracket 54 to lock the platform in place. As shown in FIG. 
19, the inverted platform exposes portions of the partially assembled disk 
drive unit through the platform opening 57. In this position, one or more 
screws 206 can be fastened quickly and easily into the housing base 22 to 
secure the solenoid unit 40 in place. In addition, appropriate screws 208 
can be fastened through the magnet unit 39 to secure the unit to the 
housing base. Moreover, a position stop plate 210 of the magnet unit 39 
(FIG. 20) can be precisely adjusted to control the swing range of the 
actuator heads 35 relative to the disks 20. 
While the platform 42 is in the inverted position, as shown in FIG. 19, the 
flex cable segment attached to the spindle leads 27 of the spindle drive 
motor can be coupled to an appropriate power supply fitting 214 as shown 
schematically in FIG. 19. This power supply fitting 214 provides 
electrical power to activate the spindle drive motor to spin up the disks 
20 substantially to normal operating speed. When this occurs, the 
read/write heads 35 of the actuator subassembly lift off or fly in slight 
spaced relation to the associated disk surfaces. During such operation, 
the actuator arms 32 can be grasped manually through the platform opening 
57 and rotated relative to the disks to reposition the heads 35 at inner 
landing zones on the disks. Such actuator displacement requires, of 
course, retraction of the alignment pin 76 by pulling upwardly on the 
now-exposed head 85 of the alignment pin. A stop pin 218 (FIGS. 1 and 2) 
conveniently defines an end limit to head displacement to align the heads 
35 at the disk inner landing zones. When this position is reached, the 
solenoid latch mechanism 104 can be adjusted as required to effectively 
park and lock the heads 35 in place. 
When the read/write heads 35 are securely latched at the inner landing zone 
positions, the platform 42 is returned quickly and easily to the upright 
orientation as viewed in FIGS. 1-18. Such return movement requires 
disconnection of the spindle motor from the power supply fitting 214, 
together with appropriate operation of the lock lever 48 to permit 
platform rotation relative to the standards 44. The lock lever 48 is 
re-engaged with the bracket 53 to relock the platform 42 in the upright 
orientation. The clamp arm 200 is quickly and easily retracted from the 
housing base 22 to permit easy removal of the partially assembled disk 
drive unit from the assembly station 10 by straight lift-off with respect 
to the cover pins 191 and 192. The partially assembled unit includes the 
actuator and disk subassemblies 14 and 18 in precision registration ready 
for subsequent final assembly, for example, by mounting of a housing cover 
(not shown) onto the housing base 22. 
A variety of modifications and improvements to the disk drive assembly 
station 10 of the present invention will be apparent to those skilled in 
the art. For example, the clamp units securing the torque spindle support 
sleeves onto the platform may be adjusted as required to accommodate 
relocation of the support sleeve reference surfaces according to the 
design characteristics of the particular disk drive unit. Accordingly, no 
limitation on the invention is intended by way of the foregoing 
description and accompanying drawings, except as set forth in the appended 
claims.