Magnetic disk storage apparatus - Patent Review 3973273

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a novel and improved data module drive utilizing a sealed interchangeable data module.

2. Description of the Prior Art

Presently known magnetic disk file data storage facilities utilizing interchangeable disks or disk packs are configured in the form of a drive that includes read/write heads, head actuator means and a drive spindle. The disk pack may contain a single disk or several disks attached to a hub suitable for mounting on the drive spindle.

In this application, "interchangeable" shall refer to a medium, such as a disk module that has universal substitution without loss of data for use on all the devices with which it is developed to work. To be truly interchangeable, all of the hardware elements involved in the mechanical, electronic and magnetic implementation of storage must have sufficient repeatability, so that the summation of all the deviations from perfection, for all elements, does not exceed the total variance, i.e. engineering tolerance allowed.

The most common pack configuration presently in use is contained in a two part plastic cover assembly. The two part cover has a circular bottom panel section that is removed by the operator prior to installation of the pack on the drive spindle, and a cylindrical side section and top that is removed at the time the pack is mounted on the drive spindle. It is apparent that the removal of the pack covers exposes the pack to contamination during a loading/unloading cycle.

An alternate pack cover configuration provides for an integral cover assembly that remains with the pack. Data heads are inserted into the pack through a cover door that is opened during pack installation. The integral cover configuration provides some improved protection of the pack compared to the removal cover type. However, in both configurations, the drive data heads are exposed to contamination during the pack loading/unloading cycle.

A typical interchangeable disk pack file facility utilizes two or more data read/write heads mounted to a carriage assembly that positions the data heads over selected data track locations. These heads must be able to read any data track written on its associated disk surface in any similar file facility. Head position may be controlled by a mechanical detent acting on the head access means; or the heads may be positioned by a closed loop servo system using a servo reference and a servo position sensing transducer. Such control of radial head positioning relative to the data track is difficult and costly in a typical high track density, interchangeable pack file facility.

With the evolution of the magnetic disk file, increased bit and track densities and resultant increased storage capacity have been realized with increased actuator speed and access time. These improvements have required more accurate radial positioning of the data head relative to the disk surface. The close spacing of the head to the disk, which may now be in the order of 50 microinches or less, requires stringent control of the disk file apparatus to avoid head/disk damage, which may be caused by particle contamination, for example. However, the challenge remains to position uniformly all data heads controlled by the reference system to a radial position tolerance equivalent to a fraction of a track width. To permit pack interchangeability, all heads in all files must be similarly positioned.

Also, the achievement of increased bit density imposes requirements for more precise control of the skew alignment of the read/write heat gap. Misalignment of the read head gap relative to write head gap will cause reduced signal output and bit timing shifts that may cause read errors. Control of the skew alignment of all data heads to assure error free pack interchangeability may represent a significant portion of the manufacturing cost of each data head.

Furthermore, presently known disk storage files utilizing interchangeable disk packs must provide means for the retraction and loading of the data heads relative to the pack disk surfaces. The head retract-load function adds cost to the file and increases the exposure of the disk pack to damage resulting from head-disk impact during retract or load.

In addition, when inserting another disk pack into the file, the disks are usually at a different temperature than the head assemblies. This temperature differential, which is reflected in the radial dimensions of the disks relative to the lengths of the head arms, presents problems in the "Seek Track" function, and therefore a warmup period is needed prior to recording or readout. Consequently, there is an undue loss of costly computer operating time.

SUMMARY OF THE INVENTION

An object of this invention is to provide a novel and improved magnetic storage apparatus.

A further object is to provide a storage apparatus wherein the requirements for manufacturing and assembly tolerances are minimized, thereby making the manufacture and assembly less expensive.

A still further object is to provide a data module file facility wherein higher data density and performance is substantially enhanced, while preserving the disk cartridge interchangeability function.

Another object is to provide a storage facility that does not require head retract mechanisms.

Another object is to provide a storage disk facility that provides improved contamination control.

According to this invention, a magnetic disk file apparatus incorporates an interchangeable sealed data module that encloses magnetic disks; accessing head arm assemblies; a movable head carriage; a drive spindle for rotating the disks; and a common frame structure to maintain alignment between the module components. When mounted to a cooperating data module drive, the spindle is engaged by means of a pulley and belt means, by way of example, with a drive motor, and the head assemblies are coupled to a bidirectional actuator, such as a linear DC motor or voice coil motor. Each movable head assembly is permanently related to an associated disk surface, and has a limited path of travel radially across the apertured disk between the outer and inner peripheries of the disk.

In a specific embodiment, the sealed module includes an access door allowing the coupling of head assemblies to the external actuator, and thereby affording radial accessing of the heads to different data tracks. External drive means coupled to the drive spindle, by means of a pulley and belt, are provided for rotating the disks. Locking means serve to maintain the head assemblies, the head carriage, disks and spindle all stationary, whenever the module is removed from the file housing.

To insure proper coupling and alignment of the head assemblies of the module to the external actuator for disk file operation whenever a similar module is inserted and engaged with the drive housing, registration, positioning and alignment means are provided. The novel configurations of the interchangeable module, and of the cooperating drive housing allow repeatability of accurate registration of the module and its components with the disk drive housing and its parts. Also, faster access is achieved due to the smaller mass of the head arm assemblies and the carriage. There is no need for head load-unload or retract mechanisms, and the total hardware for the disk file system is substantially reduced and simplified. The need for precise radial head position adjustment is eliminated. Additionally, the sealed module enjoys contamination control and therefore experiences less error and data loss.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail with reference to the drawing in which:

FIG. 1 is a side elevational view representing the insertion of an interchangeable data module into a drive housing, in accordance with this invention;

FIG. 2A is a top plan view illustrating the interconnections that function to load the module into engagement with the drive housing;

FIG. 2B is a partial plan view denoting the condition of disengagement of the module;

FIG. 3 is a sectional view taken along lines 3--3 of FIG. 2A, depicting detailed structure of the novel data module of this invention;

FIG. 4 is a perspective view of the tray or receptacle to which the module is seated and aligned relative to the drive housing;

FIGS. 5 and 6 respectively are perspective diagrams of the door and door locking mechanisms that allow sealing of the module when the module is removed from the drive, and opening of the module to engage the module head carriage and electrical connection means with the drive when the module is loaded into the drive;

FIG. 7 illustrates a section of the door locking actuator mechanism;

FIG. 8 is a partial sectional view, taken along lines 8--8 of FIG. 5;

FIG. 9 is a front view of part of the module used in this invention;

FIG. 10 is a top view of the door opener mechanism;

FIG. 11 is a top view of the load cart, shown in FIG. 3, used to load and register a data module in the drive housing;

FIG. 12 is a sectional view of a guide, taken along lines 12--12 of FIG. 11;

FIG. 13 is a section taken along lines 13--13 of FIG. 11;

FIG. 14 is a section taken along lines 14--14 of FIG. 10;

FIG. 15 is a side sectional view of a coupling device and coupling latch plate utilized in the novel apparatus;

FIG. 15A is a perspective view of a slotted actuator sleeve for accepting a key as employed in the device of FIG. 15.

FIGS. 16A and 16B are partial front views of the coupler of FIG. 15, in unlocked and locked positions respectively;

FIG. 17 is a front view of a coupler support and actuator;

FIG. 17A is a plan view of a detent bearing employed in the structure of FIG. 17;

FIG. 18 is a right side view of the upper portion of FIG. 17;

FIG. 19 is a left side view of the same portion of FIG. 17;

FIG. 20 is a top view of the assembly of FIG. 17;

FIG. 21 is a side view of the carriage locking mechanism;

FIG. 22 is a top sectional view of the disk brake mechanism;

FIG. 23 is a side view, partially in section of an alternative coupling device;

FIG. 24 is a front view of the collet chuck incorporated in the coupling device of FIG. 23; and

FIG. 25 is a side view, taken along lines 25--25 of FIG. 24.

Similar numerals refer to similar elements throughout the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with an embodiment of this invention, an operating disk file apparatus includes an interchangeable sealed data module 10 containing a number of rotary magnetic disks 12, movable accessing magnetic heads 14, spindle 16, and having an exposed drive pulley 18. The module 10 is engageable with a data module disk drive housing 20, which includes a head actuator such as a voice coil motor 22, and a drive motor 24, to rotate the disks (see FIGS. 1 and 3). The module 10 may be easily and conveniently replaced and interchanged with similar modules. A coupling device 26 serves to connect the head actuator 22 to a carriage 23 supporting the head assemblies 14, and electrical connection means 28 (FIG. 9) are provided to conduct signals to the magnetic heads. The head assemblies 14 (only four being shown for simplicity and convenience) may include one servo head that affords track following of the data tracks. In addition, more than one head assembly 14 may be provided for each disk data surface.

As shown in FIG. 1, in order to assemble the module 10 to the drive housing 20, the operator by means of a handle 30 lowers the module into a shroud or tray 32 (see FIG. 4). The tray has sloped or tapered sides 34 that coarsely position the cartridge, and provide a data plane or reference for alignment.

The module also has alignment cavities 29 in its lower surface which align with protruding guides 39 in the tray 32. The combination of the module covers, the sloping side walls of the tray 32, the guides 39, and the cavities 29 serve to accept the module from the approximate position provided by the operator and align the module with greater precision as the module is lowered into the tray.

All of the noted guiding elements are positioned so that only the data module covers are contacted during operator loading into tray 32. Pulley clearance aperture 19 accepts the module pulley 18, foot clearance aperture 38 accepts the module registration feet 36, and load pin clearance aperture 35 accepts module load pin 66.

The tray 32 is supported and guided by two rollers 70 which run in grooves 72 in guide structures 60. The tray is further supported by a mounting plate 125 which is attached to the module retaining arm 124. The tray 32 is aligned in the direction of proposed movement of the module to enable the module to engage the coupling mechanisms provided by the stationary file housing 20.

Once the module 10 is seated in the shroud 32 by the operator in a desired alignment, a hinged door 40 is closed (as depicted by the arrow in FIG. 1), simultaneously causing the rotation of a camshaft 42 that is coupled to the door 40. The rotary motion of the camshaft 42 is translated to linear motion to accomplish a series of mechanical steps for linking the module 10 with the file housing 20 in an operating condition.

With reference to FIGS. 2A and 2B, the mechanism for engaging and disengaging the drive pulley 18 of the module 10 with a drive belt 44 and drive motor pulley 25 is illustrated. In the disengaged condition as illustrated in FIG. 2B, a pair of pivotable idler arms 46 are positioned to hold the belt 44 in an extended position while the belt 44 is also engaged with the drive motor pulley. The idler arms are spring biased so as to tension the belt. The arms are aligned with the belt so that a force applied at point A will cause the arms to be forced rearward in the direction of the motor. The idler arms and belt are aligned so that angle .phi..sub.1 is less than .phi..sub.2 at all times to assure that a force applied at A will force the arms rearward. When the module 10 is inserted into the shroud 32 and properly aligned and registered by means of the feet 36, the pulley wheel 10 of the module 18 is positioned within the perimeter of the belt 44. As the module is moved forward toward engagement with the drive housing, the data module pulley 18 contacts the belt at point A thus forcing the arms rearward. The idler arm length is selected so that the idler arms and their attached belt pulleys will pivot around the outside of pulley 18, as the data module is moved forward into engagement with the file housing. As the idler arm pulleys reach a point where they contact the belt in planes tangent to the outside diameter of the motor pulley and the data module pulley, further motion of the data module pulley 18 requires motion of the motor pulley. The two idler arms are connected together by two gears 48 to assure that they move in unison. The arm spring bias is supplied by a torsion spring 49 which supplies the necessary torque.

To ensure suitable coupling of the belt with the drive pulley 18 and drive motor 24, a motor mount plate 50, to which the drive motor 24 is attached, serves to tension the belt 44 against the motor 24 and pulley 18 of the module, in conjunction with a spring 52 attached to the plate 50. The mounting plate 50 is pivotable about a fixed point 54 and is moved along rollers 56, as the motor 24 is urged forward in the direction toward the acttuator 22. As the data module completes its engagement motion, the idler pulleys reach their tangent position, and the forward motion of the data module pulley 18 moves the motor and its mounting plate 50 in a direction toward the data module. Cam 51 mounted on the mounting plate 50 engages ball bearings 53 on the idler arm 46, and thus forces the idler arm pulleys out of contact with the drive belt 44. The drive belt is not tensioned between the data module pulley and the spring loaded motor mounting plate 50. In this manner, the belt 44 is tautly engaged with the motor drive 24 and the pulley 18, so that the rotary drive motion of the motor 24 may be translated to the pulley 18 for rotating the disks 12.

With reference to FIGS. 3 and 11, the module 10 and tray 32 are moved forward to the data module loaded position by the linear motion of load cart 64. The load cart is operatively connected to camshaft 42 by toggle mechanism 129, link 131 and cam follower lever 133. The toggle mechanism 129 is connected to the load cart 64 by toggle pivot pin 135. The toggle 129 is supported at its end opposite pin 135 by pin 137 which is supported by load cart and base 139. The toggle mechanism 129 provides a rapid loading motion at the start of module loading and a high retaining force when the module is registered in the file housing. The load cart 64 is supported and guided by ball bushings 141 and bearing roller 143. The bushing 141 is supported in turn by support rod 145 and the bearing roller 143 by cart support and retainer cam track 147.

At the time of operator module handling, the load cart 64 is positioned so that it will not contact the data module. Initiation of the module loading cycle through the closure of door 40 moves the load cart 64 in the direction toward the drive 20 and voice coil motor 22.

The load cart 64 incorporates a spring loaded pin 65 suited to provide a registration force against module load pin 66. The cart 64 also incorporates a load pin U-block 67 suited to engage to module load pin 66, and position this pin in alignment with spring loaded pin 65 as the load cart is moved forward.

As the cart 64 moves forward, roller 149 rides down track 147 causing module retainer 153 to rotate counterclockwise and engage retaining slot or load pin 66. Simultaneously, tray 32 is moved rearward in relation to the motion of cart 64, thus moving the data module and its load pin 66 into engagement with spring loaded pin 65. The relative motion of tray 32 to the load cart 64 is provided by the action of mounting plate 50. The mounting plate 50 is supported by pivot pin 54 carried in module retainer 153. The plate 50 is also supported by link 55. Counterclockwise rotation of the retainer 153 moves mounting plate 50 horizontally in a direction toward load pin U-block 67. When the shroud 32 and module 10 are in their forwardmost position, a conical recess or socket 74 engages a locating ball 76 that is fixed to the baseplate of the drive housing 20. At such time, feet 36 are positioned on the flat ways 62 and abut the side 78 of the way structure, so that the module is stable in a fixed position.

When the module becomes properly positioned with reference to the drive housing, and the ball 76 and socket 74 become engaged, a coupling mechanism 26 illustrated in detail in FIGS. 9, 15, 16A, 16B, and 17-20 acts to connect the linear motor 22 to the head carriage assembly 23. The linear actuator 22 may be a voice coil motor, by way of example, that includes a bobbin structure on which a coil is disposed. The structure is located in a magnetic field supplied by permanent magnets. Current signals are fed to the coil to actuate the bobbin and to move the bobbin in a predetermined direction for a given distance. The bobbin is coupled to the head carriage assembly 23, so that the heads 14 may be moved to selected data tracks on the surfaces of the disks 12.

To accomplish an effective connection of the voice coil bobbin to the head carriage, a retention mechanism holds the bobbin in a position for mating and locking with the carriage assembly 23 in the data module 10. The mechanism also activates the coupler 26 and releases a latch that holds the carriage 23 securely in its home position. To unlatch the carriage 23 and to release the retention mechanism from the bobbin 22, a coupling driver 82 is aligned with a key slot of a detent bearing 84. In turn, the slot 85 of an acceptor 86 (FIG. 20) is aligned parallel with the longitudinal axis of the bobbin of the voice coil motor, and also parallel to a bayonet pin 88 located in a bobbin eccentric shaft 90. In this mode, a solenoid 92 (represented by arrow) is energized causing a cable 94 that links the solenoid to the drive 82 to be under tension. The driver 82 is pulled down with a key 96 engaging a slot in the detent bearing 84 with the acceptor 86 in its lowest position. A pivot lever 98 is rotated to its extreme counterclockwise position, and brings link 100 and latch release lever 102 to their extreme upper position. At this point, a microswitch 104 is in its normally open position, and a spring 106 is under compression. A cam 108 that is located on the outer surface of the acceptor 86 forces a yoke 110 back. Also, a nesting plate 112 that is attached to the yoke 110 through the two slots 85 is pulled back to its extreme position. The plate 112 is thus forced to its extreme lower position, by two torsion springs 116. When the carriage latch lever 102 is released, and the acceptor shaft 86 is retracted, and the nesting plate 112 is dropped out of the way, the bobbin and carriage are automatically locked together as a unit, and current signals may be applied to the bobbin coil to accomplish head accessing.

Before the voice coil bobbin and head carriage assembly can be connected, it is necessary to open a sealed door structure 122 that is part of the module 10. The door structure must be opened in advance of the meeting and locking of the coupling mechanism 26 between the voice coil motor 22 and the head carriage 23. To accomplish the opening of the door 122, the rotary force of the camshaft 42 is translated to linear motion. In turn, the translated linear motion is amplified by mechanisms having mechanical advantage, while providing linear force in a plane perpendicular to that of the load cart motion.

With reference to FIGS. 5-8, the motor 122 is first moved outwardly in the module structure away from its seal 123, before the door can be slidingly opened to allow connection of the actuator bobbin to the head carriage.

The outward motion of door 122 is accomplished at the time the module is loaded into tray 32. The tray incorporates door unlatch post 63. This post contacts door unlatch button 124 at the bottom of the module. In response to contact with post 63, the button 124 applies a vertical force and motion to connecting link 126, thereby rotating a latch lever 128 about a pivot 130. As a result, a latch push rod 132 is moved laterally causing an operating finger assembly 134 to rotate around a pivot pin 136. To open the door and break the door seal, one finger 134a pushes the door 122 outwardly. The extent of movement of the door is limited by the cam contour of latch lever 128.

The door 122 now is seated in a guide slot 140, to permit sliding of the door sideways and to accommodate the fixed bobbin structure that is being approached by the module 10 and its head carriage assembly 23. With reference to FIGS. 5-8 and 10-14, a follower of the camshaft 42 actuates a cam plate 142 to move in a direction (upward as depicted in FIG. 10).

As depicted in FIGS. 10 and 14, the cam plate 14 is supported and guided by guide shafts 163. The guide bushing 16 and washer 165 locate the cam plate 142 vertically by means of snap rings 167. The cam follower bearing 146 engages the cam slot in camplate 142 and is in turn mounted to pulley arm 150. The pulley arm is pivotably supported by a door frame 144 which is rigidly mounted to load cart 64. The door opening mechanism, depicted in FIG. 10, is illustrated in the "Door Open" position. Rearward (upward in FIG. 10) motion of the load cart will bring cam follower bearing 146 into engagement with inclined track section 145. Further rearward motion of load cart 64 would then cause a counterclockwise motion of pulley arm 150, thus moving arm pulleys 155 to the right tending to close the module door. The motion of cam plate 142 by the cam shaft 42, accelerates the motion of the door opening action to assure that the door 122 is fully open prior to module registration.

Longitudinal door motion in a direction perpendicular to the motion of travel of the cart 64 is provided by a finger assembly 134 which is carried on a push rod 154. Finger 134, which engages door cavity 157, and is pivotably mounted to push rod 154, is spring biased into engagement with the door cavity 157 by a torque spring 159, as shown in FIG. 6.

When tray 32 is moved away from spring loaded pin 65 at the end of the module "Unload" cycle, finger 134 is depressed downward by contact with the front end of tray 32. Push rod 154 rides in a slotted sleeve 156. A key 160 extends from the side of rod 154 and is attached to a cable 158. The cable is wrapped around the pulleys 152 (the axles being fixed to frame 144) and two pulley arm pulleys 155. The ends of cable 158 are tensioned by springs 169, as shown in FIGS. 6 and 10.

The stroke multiplication provided by the pulley system (2:1) and the pulley arm (2:1) provide a 4:1 multiplication of the input of the cam plate 142.

A cam slot rise 171 provides an overtravel motion at the end of door closure to assure complete longitudinal motion of door 122. The overtravel is accommodated by tension springs 169.

With reference to FIG. 21, the transducer carriage 23 is supported on six ball bearing rollers 162. Four rollers are mounted with their rotational plane 45.degree. to the vertical and contact two inclined way surfaces lying in a plane parallel to the direction of carriage access motion. The bearings so located include forward bearing 162a, rear bearing 162b and two additional bearings at the opposite side of the way (not shown).

The carriage 23 is biased downward against the way 27 by the action of two outrigger ball bearing rollers 166a, b. Outrigger bearing 166a runs along the under surface of fixed way 168. The fixed way 168 is attached to the data module casting or frame assembly 179. The second outrigger ball bearing 166b is biased downwardly by spring loaded way 172 (See FIG. 9). The spring bias on the spring loaded way 172 is provided by depression spring 174 which bears against a snap ring mounted on way pin 176. The way pin 176 has a snap ring at its top surface which bears against the top side of the spring loaded way 172. The spring loaded way is supported at its side opposite the ball bearing roller 166 by two ears that contact the data module base casting 170. The action of the two support ears and the spring loaded pin 176 tend to bias the spring loaded way 172 downwardly to load against ball bearing 166b.

The action of the spring loaded way 172 acting on ball bearing 166b tends to pivot the carriage assembly 23 in a counterclockwise direction when viewed through the front of the cartridge, as in FIG. 9. As the carriage rotates, the outrigger bearing 166a bears against the fixed way 168. The carriage incorporates a vertical U-section at its rearward extremity which is utilized to mount the data module transducer arm assemblies 14. The vertical extending U-shaped channel section of the carriage contains horizontal locating slots to position the data module arms. The arm is clamped within the channel section by the action of the arm clamp bolt 180. This clamp bolt extends through the two sides of the vertical U-section, and a nut (not shown) is used to tighten the bolt and provide a clamping force on the arm 14.

The data transducer arm 14 mounts a data transducer at its outward extremity. The transducer is suspended by a suspension element which serves to provide a downward bias force to hold the transducer in intimate contact with the data disk surface, when the disk is not rotating. The carriage arm mounting channel section may be extended vertically to accommodate a number of data arm assemblies.

When the data module 10 is removed from the data file, it is desirable to lock the carriage assembly 23 in a fixed position to prevent damage of the data module components, and to provide a fixed position of the transducer carriage for subsequent coupling to a voice coil motor bobbin assembly, when the data module is reinserted into a similar drive housing 20. The latching of the transducer carriage 23 is accomplished by latching of latch arm 181, as depicted in FIG. 21. The carriage latch arm 181 is pivotably mounted about the latch pivot pin 182. The latch arm 181 incorporates a latching detent notch 184 which serves to engage the extension of the carriage bearing axle 185 for bearing 166a. The latch arm 181 is normally biased upward so that detent notch 184 is engaged with the carriage bearing by the action of latch torsion spring 186. The latch torsion spring 186 is mounted about the pivot pin 182 and has extensions that bear against the data module casting 170 and against the lower surface of the latch lever arm.

The latch lever arm 181 incorporates an interposer surface 188 along its top surface, which serves to prevent the latch from being positioned in its fully latched position, except when the carriage is at the home position. Interposer pin 190 extends from the side of the carriage 23, so as to provide an interposer to prevent upward latch motion in the event the carriage is to the right of the home position, where the axle 185 may be so close to the latch pivot pin 182 as to provide insufficient interposing action from the axle alone.

Unlatching of the carriage latch arm 181 requires a counterclockwise rotation of the latch arm, as illustrated in FIG. 21. The force to overcome the action of latch torsion spring 186 may be applied to the latch arm 181 through the latch pin 192. The latch pin 192 engages with latch release lever 194 when the data module 10 is inserted into the drive housing 20, and is at the registered position. An upward motion of the latch release lever 194 will cause the latch arm 181 to rotate in the counterclockwise direction and disengage from the carriage bearing axle 185.

The carriage latch plate 220 is attached to the outer face of the carriage 23 and provides a means for the carriage to be connected to the voice coil bobbin 22.

FIG. 22 is a section view of the data module looking downward into the top of the data module pulley 18. The spindle brake serves to lock the data module spindle, so that the disks will not rotate when the data module is removed from the drive, thus minimizing the chance of damage to heads and disks by vibration in shipment or during handling. The inner diameter of the pulley 18 serves as a brake drum. Two brake pads 206 are mounted on brake bands 204, which are in turn attached to a mounting bracket 200. The mounting bracket incorporates two ears 202 which extend out from the outside diameter of the module casting lower bearing boss, so as to provide a surface parallel to the brake drum for the attachment of the brake bands 204. The brake bands are riveted to the ears 202 on the bracket 200. The brake band 204 is at its opposite end riveted to operating link 208, which is in turn attached to a link 210 connected to brake lever 212.

The braking force is supplied by the spring action of the brake band 206, whose normal diameter is considerably larger than that of the inner diameter of the data module pulley 18. The action of the two brake bands serves to rotate the brake lever 212 in a clockwise direction. The brake lever is supported on brake lever pivot 214, which is mounted to the mounting bracket 200.

The data module spindle brake may be released when the module is inserted into the data drive assembly. Fixed brake operating cam 216 is positioned in the drive assembly so that the brake lever 212 will come into contact with the cam surface near the end of the insertion stroke into the drive assembly. As the data module is moved in a direction to the right, as viewed in FIG. 22, the contact of lever 212 with the fixed cam surface 216 will force the brake lever 212 to rotate in a counterclockwise direction, thus applying a tension force to the brake bands. This tension force will tend to move the bands and their attached brake pads out of contact with the inner diameter of the data module pulley, thus freeing the pulley for operation by the drive spindle motor 24.

The brake operating cam 216 extends horizontally in a shape suitable for insertion between the top of the pulley 18 and the data module covers.

FIGS. 15, 15A, 16A and 16B illustrate a preferred embodiment of a bobbin-carriage coupling device. FIG. 15 depicts a section view of the bobbin coupling assembly and its mating latch plate 220. The coupling assembly is contained within the voice coil actuator bobbin 222, and the latch plate 220 (see FIGS. 9 and 15) is mounted to the end of carriage 23. The latch plate provides piloting means to locate the bobbin assembly 222 in vertical and horizontal position relative to the carriage. The latch plate 220 also provides a latching surface 224 at its carriage side, which provides a mating surface to mate with cross pin 226 in the bobbin coupling assembly. Latch plate circular pilot hole 228 engages with and initially locates coupling pin assembly 244. Latch plate circular guide 229 provides final alignment by engaging bobbin pilot 230. The entrance to the guide 229, the edge of the bobbin pilot 230, and the end of pin 244 are all tapered to aid in the aligning of the bobbin pilot to the latch plate circular guide 229.

When the bobbin coupling is in its uncoupled position, and a data module is moved toward the bobbin for subsequent coupling, the cross pin 226 is in the position, as illustrated in FIG. 16A. Latch plate 220 incorporates a coupling pin clearance slot 232 (FIG. 9) to permit the coupling pin 226 to pass through the latch plate 220 on initial engagement of the latch plate with the bobbin assembly.

Rotational alignment of the bobbin assembly about the axis of access motion is provided by the interaction between latch plate top guide slot 234 and bobbin top in 236. Parallel alignment between the access axis center line of the bobbin assembly and the access axis of the data module carriage is provided by mating pin surfaces which are carried in both the data module carriage and the bobbin. The face of the two carriage lower pins 238 engage with the face of two bobbin bottom pins 240. The face of carriage top pin 242 engages with the face of bobbin top pin 236. The carriage mounted pins 238 and 242 are held in intimate contact with bobbin mounted pins 240 and 236, respectively through the action of coupling pin assembly 244. The coupling pin assembly 244 is adapted to reciprocate along an axis parallel to the access axis of the bobbin, and is also suited to rotate bidirectionally 45.degree.. The pin assembly 244 is spring biased by Belleville spring washers 246 in a direction toward the VCM actuator 22. The spring washers 246 bear against an internal wall surface of the bobbin pilot assembly 230. A bias force from the washers 246 is applied through washer 248 to the pin assembly 244.

If the cross pin 226 is inserted through the latch plate pin hole 228 and pin clearance slot 232 and is subsequently rotated 45.degree., the cross pin 226 may no longer be drawn back through cross pin clearance slot 232. If the pin assembly 244 is then forced in a direction to the right, as illustrated in FIG. 15 relative to the pilot assembly 230, the action of the cross pin 226 in bearing against the latching surface 224 will tend to draw the bobbin assembly 222 into contact with the data module carriage assembly 23, and the two bobbin bottom pins 240 will be forced into contact with the two carriage bottom pins 238. The bobbin top pin 236 will be forced into engagement with carriage top pin 242.

Longitudinal and rotational control of the pin assembly 244 to accomplish automatic coupling and uncoupling is provided by the bobbin coupling assembly. The bobbin pilot assembly 230 is retained in the bobbin assembly 222 by snap ring 254. Rotational positioning of the bobbin pilot assembly is provided by locating pin 256, which engages a slot in the top of the bobbin pilot assembly 230.

When the coupling is in its engaged position and attached to the data module carriage assembly, washer 248 bears against a shoulder at the rear of the pin assembly 244. The longitudinal and rotational control of the pin assembly 244 is provided by means of an eccentric shaft 260 which accommodates a mounted needle bearing 262 and an actuator cam 264. The needle bearing provides longitudinal positioning of the pin assembly 244, and the actuator cam provides rotational positioning of the pin assembly 244.

FIG. 15 illustrates the coupling assembly in the uncoupled position. In this mode, needle bearing 262 bears against actuator sleeve 266. The actuator sleeve 266 incorporates a bore designed to accommodate the shouldered end of pin assembly 244. The depth of the bore in the actuator sleeve 266 is slightly longer than the length of the shouldered section of pin assembly 244. When the eccentric shaft 260 is rotated (as in FIG. 15) to bring the needle bearing 262 into engagement with the outer end of sleeve 266, the sleeve is moved to engage washer 248, thus removing the load of Belleville spring washers 246 from the pin assembly 244. Further motion of the eccentric shaft and the needle bearing 262 causes the actuator sleeve 266 to move to the left, so that the end of the internal bore in sleeve 266 engages the end of pin assembly 244. Further motion of the needle bearing 262 will thus cause the pin assembly to move to the left.

Ball arm 252 engages ball slot 258 in actuator cam 264 in the uncoupled position, as in FIG. 16A. Clockwise rotation of eccentric shaft 260 will cause the rotation of the actuator cam 264, and thus cause movement of ball arm 252, so as to rotate pin assembly 244 counterclockwise, as viewed in FIG. 16B. The eccentric shaft is designed for approximately 112.degree. of total rotation. As illustrated in FIGS. 15 and 16A, the bobbin and pin assembly is shown in its uncoupled position with the cross pin 226 at 45.degree. to the vertical, and the pin assembly 244 extended outwardly from the bobbin assembly 222 by the action of eccentric shaft 260. In this position, actuator cam 264 bears against a stop surface 267 with counterclockwise stop 265 (see FIGS. 15 and 16B).

When viewed from the top, the eccentric shaft is positioned so that the high point of the eccentric relative to pin assembly 244 is approximately 20.degree. counterclockwise from the access center line of the bobbin assembly. The thrust load supplied by the Belleville washers 246 tends to force the eccentric shaft to rotate in a counterclockwise direction, thus forcing counterclockwise stop 265 into intimate contact with stop surface 267.

During normal loading of the data module into the drive assembly, when the carriage 23 is brought into position to where the cross pin 226 is positioned behind surface 224 in cavity 292, the coupling is ready for actuation to couple to the carriage assembly. The eccentric shaft is rotated in a clockwise direction, when viewed from the top, to couple the bobbin assembly to the carriage assembly. During initial coupling rotation of the eccentric shaft 260, ball slot 258 tends to rotate pin assembly 244 through the action of ball arm 252. As the eccentric shaft 260 is rotated clockwise about 20.degree., pin assembly 244 is extended slightly further from bobbin assembly 222, and cross pin 226 is rotated approximately 20.degree. to a position about 70.degree. from the vertical. Additional clockwise motion of the eccentric shaft 260 completes the rotation of the cross pin to the horizontal position illustrated in FIG. 16B.

At the position illustrated in FIG.