JPS62222483A - Magnetic disc unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the field of magnetic disk storage units. More particularly, the present invention provides a ruggedized structure suitable for use in hostile or harsh environments, capable of withstanding loads or stresses such as shock, vibration, and extreme temperatures, and capable of operating in any position. The present invention relates to magnetic disk storage units. The unit of the invention is particularly suited for military applications, but can also be used in other harsh environments such as oil and gas well drilling and seismic exploration.

Both magnetic tape recorder units and magnetic disk storage units have been well known in the art for many years. Although tape units suitable for heavy-duty applications are available, improved disk units are needed. The present invention
In particular, it provides an advanced disk unit that is housed in a compact envelope and has an improved ability to operate in extreme vibration and temperature environments.

Referring to FIG. 1, the outer housing of the unit of the present invention is shown. The housing 10 includes a removable cover plate 1
4, the cover plate 14 is attached to the main housing section 12 by a plurality of screw fasteners 16. Housing section 12 and cover plate 1
4 is made from metal, especially aluminum. A curved cover 18 is attached to the housing section 12 and includes a release latch mechanism for locking and releasing the housing from a vibratory cradle (not shown) with a shock mount to which the unit is mounted. It has 20. Housing section 12 has mounting slots 22 along its length on both sides.
and these grooves cooperate with corresponding launches or guides of the cradle. To properly seat the unit in the cradle (and to ensure proper alignment with the electrical connections at the rear end of the unit), the grooves are offset on each side of the unit (as are the guides on the other side of the cradle). ). Since the groove and the mating guide are asymmetrical, the unit can only be installed in one position (i.e. the correct position) in the cradle.

2, 3 and 4, details of the magnetic disk unit of the present invention are shown. A magnetic disk 24 (as is known in the art) is mounted on a rotating plate or table 26 from which a rotating spindle 28 extends. The spindle 28 is preferably mounted and supported via an elastomeric member 33 in a bearing 30.3I. Magnetic disk 24 is locked to rotary table 26 by top plate 34 which is releasably attached to table 26 by screws 36. As best seen in FIG. 3, the top plate 34 overlaps the inner edge of the central opening of the disc 24 and locks the disc to the table 26. The table 26 is driven by a motor 37 whose stator 38 is mounted on a housing segment 40 and rotor 42 is mounted on a skirt 44 attached to the rotary table 26. motor 37
When electrical power is applied to the table 26 and disk 24, the table 26 and disk 24 rotate as desired in a clockwise or counterclockwise direction, preferably in a counterclockwise direction.

The read/write head mechanisms 46 are the same on both the upper and lower sides of the magnetic disk 24 (both sides can contain data), and only one of them will be described.

The read/write head mechanism 46 includes a contoured bent beam 50.
It has a magnetic pickup head 48 mounted on the end of the head. The bending beam 50 is attached to a support plate 52 that is attached to a head carriage 54. The bending beam 50 holds the head 48 directly above but in contact with the disk 24 during operation of the unit, and the bending beam 50
0 flexes to raise and lower the head 48 as it moves back and forth between the home position and the operating position, as will be discussed in more detail below.

The head carriage 54 is mounted for linear movement on a pair of cylindrical guide rods 56,58. Also, the unit is
It has a third cylindrical guide rod 60. The counterweight assembly 62 is mounted on the guide rod 58.60 for linear movement. Guide rods 56, 58, 60 each extend between and are supported by an end plate 55 mounted on the front end of housing section 12 and a support block 57 mounted on the floor of housing section I2.

As best seen in Figure 4, the head carriage 5
4 is mounted for linear movement on the rod 56 by upper and lower roller bearings 64, 66, said roller bearings being rotatably mounted on the carriage 54 and engaging the rod 56 from above and below. The Herad carriage 54 is also mounted for linear movement on the rod 58 by a pair of roller bearings 68, 70, said roller bearings being rotatably mounted on the carriage 54 and mounted on the rod 58 from above and below, preferably with elastomeric members. (not shown).

Similarly, the counterweight assembly 62 is mounted for linear motion on the rod 60 by upper and lower roller bearings 72, 74, said roller bearings being preferably elastomeric members (
(not shown) to the counterweight assembly 62, and the assembly 62 is attached to the rod 58 for linear motion.
by a pair of rollers 76, 78, said rollers being rotatably mounted to assembly 62 and connected to rod 58.
from above and below, again preferably via an elastomeric member (not shown).

As will be appreciated from the foregoing, the head carriage 54 and counterweight assembly may radially or
4, it is movable back and forth in a linear direction, parallel to the radial line. Also, the balance weight is the weight of the Herad Carriage 5
4, the weight of the support plate 54 and the bending beam 50. This weight balancing provides static and dynamic balance in the assembly and reduces the effects of shock and vibration.

Head carriage 54 and counterweight assembly 62 are each attached to a continuous drive belt 80, preferably stainless steel. A drive belt 80 extends between and around a drive capstan 82 and a rotatable idler 84. The stepping motor 86 is connected to the capstan 8
2 to move the belt 80 step by step in response to human input to the stepping motor. Head carriage 54
is attached to one leg of belt 80 and counterweight assembly 62 is attached to the other leg of belt 80. Thus, the head carriage 54 and the balance weight assembly 6
2 moves by the same m and in the opposite direction when the stepper motor is activated.

This equal and opposite action of head carriage 54 and counterweight assembly 62 contributes to the operational stability of the present invention and to the improved shock and vibration resistance of the unit.

Head carriage 54 and counterweight assembly 62 are each attached to drive belt 80 by the same gripping mechanism, one of the gripping mechanisms (the one associated with counterweight 62)
Let's talk about. Belt 80 is gripped between a depending portion 88 of counterweight 62 and an axle or clamping finger 90 eccentrically mounted on rotatable spring element 92 . belt 8
0 is tightening (, J IJ finger 90 and under the nail j1 ≦ min 88
and this belt passes between the clamping finger 90 and the section 8 when the eccentric is in the actuated or locked position.
8 and is gripped and locked. Conversely, the counterweight 62 rotates the screw 92 to move the eccentric body 90 to the depending portion 8.
It can be released from the belt 80 by moving it away from the belt 80.

Locking screw 94 overlies and contacts the head of screw 92 to lock screw 92 and eccentric 90 into position for engagement with belt 80 .

As will be appreciated from the foregoing, an actuation signal to stepper motor 86 causes belt 80 and head carriage 54 to
is driven to precisely position the read/write head 48 at the desired position with respect to the disk 24. When the head 48 is in the operating position above the disk 24 for reading or writing, the head is both close to and spaced from the disk to avoid contact with the disk and to avoid damage to the disk. It is important to keep it away from While the disk is rotating, the disk 24
An air cushion or air support effect is established between the head 48 and the head 48, which causes the head 48 to act like a flying head. However, in accordance with the present invention, when disk 24 is not rotating (or if head retraction is programmed), head 48 retracts to a "home" or "reference" position where the head is stored on a landing pad 96 that stores and protects the If the rotation of the disk stops for any reason, the stepper motor 86 is operated to drive the belt 80 in a direction that moves the head carriage 54 away from the disk 24.

As the head assembly is retracted, the lower cam follower 98 of the bending beam 45 (follower 98 is preferably spherical or hemispherical) contacts the leading edge 100 of the membrane element 101, thereby causing the head 48'' to move toward the disk. 24 (i.e., moved in a direction perpendicular to the disk 24).A spherical or hemispherical cam follower 98 is raised from 5.
It will be appreciated that there are rapid angular changes necessary to raise and lower the door 48 quickly over relatively short linear distances.

Further retraction causes the read/write mechanism and head 48 to move parallel to the disk 24 (with the head 48 away from the disk), and then the cam follower 98 drops behind the trailing edge 102 and the head 48 hits the landing pad. 96 to the rest position. Similarly, when a signal is sent to stepper motor 86 to move the read/write mechanism to the operating position to position head 48 above disk 24, cam follower 98 contacts trailing edge 102 and lifts head 48 off landing pad 96. raise. Then, with the head 48 a considerable distance upwardly from the disk 24, the read/write mechanism and the head 4
8 moves parallel to the disk 24.

As the cam follower 98 falls along the leading edge 100 of the cam member 101, the head 48 is lowered to an operating position just away from the surface of the disk 24.

This portion of the head 48 perpendicular to the plane of the disk 24 as the head 48 moves into the retracted or operational position is a very important feature of the present invention and prevents the head from being dragged across the plane of the disk. This protects both the head and the disk.

The magnetic disk unit has an electro-optic sensor 104 that functions to deactivate the stepper motor when head carriage 54 and head 48 reach a fully retracted position. A flag 106 is attached to the head carriage 54. When the head carriage 54 reaches the fully retracted position, the flag 106 enters the slit of the sensor 104. Then, when carriage 54 and head 48 reach the fully retracted position, flag 106 interrupts the optical path of sensor 104, which causes sensor 104 to generate an output signal that terminates operation of stepper motor 86 in the retract direction.

This unit interacts with the skirt 44 to sense an index notch 118 or other indication in the skirt 44 and determines a "zero" index position that coordinates the angular motion of the disk with the axial motion of the head 48. A sensor 116 is included. Skirt 44 is made from a magnetic material such as iron. Index notch 118
is actually an air gap in the skirt 44 of magnetic material iron. Sensor 116 senses changes in the magnetic path (reluctance) in index notch 118. In this way, the angular position of the stored data (and its readout) and the axial position of the head 48 can be reconciled from the reference position to retrieve the desired information.

The unit also includes a feature that will retract head carriage 54 and head 48 to a fully retracted position if power is interrupted for any reason. Interruptions in power may occur due to intentional interruption, power failure, or when the front cover latch 20 is actuated to the open position to remove the unit from its cradle. Opening of the latch 20 is sensed by a magnetically operated switch 108 which shuts off power to the unit. Regardless of the cause of the power interruption, the voltage to the spindle motor 37 drops to zero. This voltage drop is sensed by the electrical control unit (Figure 5). The spindle motor, still rotating, is used as a generator for the stepper motor and stepper motor microprocessor that drives the head carriage 54 and head 48 to the fully retracted position.

Cover 14 includes a channel 109 along its periphery as shown in FIG. Seal 110 is compressed between cover plate 14 and housing 12 when housing 12 is installed to seal the interior space of the unit. (The cover plate 14 and the housing 12 have alignment holes 11 that accommodate screws 16, only a few of which are shown.)
It will be understood that there are 2. Hole 112 is preferably located on the underside of seal 110. ) The interior of the sealed unit is filled with an inert gas, such as Freon, to establish and maintain a constant environment for the system. The rotational movement of the disc 24 causes a circular flow of Freon gas within the sealed unit, which flows through the internal filter 114 to constantly filter out contaminants appearing in the gas (from the discs and other components in the system). .

The combination of sealing and internal filter provides a particularly stable and contaminant-free environment.

The unit is modular for ease of assembly, disassembly and repair. Rotary table 26, spindle 28
, the top 34 and the motor 37 constitute one module. Complete read/write mechanism (head 48, beam 50, plate 5
2), head carriage 54, balance weight assembly 62
, guide 56.58.60, stepper motor 86, end plate 5
5 and support block 57 constitute another module. Front cover 18 with latch 20 and switch 108 constitutes another module.

FIG. 5 shows a block diagram of an electronic control system suitable for use with the unit of the present invention. As shown in Figure 5,
When the spindle servo 204 generates a drive signal to the spindle driver 206, power is applied to the spindle motor 37, and the motor 37 rotates. spindle motor 3
The speed 11' of 7 is synchronized to the spindle servo 204 via the spindle zero index 208 signal and the crystal oscillator 210 frequency. The spindle zero index signal is generated by zero index magnetic sensor 116. Thus, at this point, the spindle motor is rotating at the desired speed and the read/write head 4 is rotating.
8 is in a predetermined location above the disc.

The electronic devices that control the operation of the read/write mechanism are as follows. When a predetermined command is received, (read/write head 48
A signal proportional to the distance traveled is generated by microprocessor 201 and converted to analog format by D/^ converters 212 and 214, which transmits the signal to stepper motor 86 via stepper servo and driver 216. . As a result, read/write head 48 will be moved to a commanded position over a given track or cylinder of disk 24. Once the command position is acquired, a unique servo pattern embedded in a track or cylinder of disk 24 is detected by track following servo 218 and
It is reformatted by converter 220 and processed by microprocessor 201 to maintain (align) the head position at the center of its disk track. This avoids off-track drift by the read/write head 48 and problems during subsequent read/write functions.

In the event of any type of power interruption (as described above), read/write head 48 and carriage 54 are returned to a fully retracted position on landing pad 96. This automatic retraction occurs when microprocessor 201 detects any of the power interruption conditions described above (e.g., magnetic switch 10
8 is actuated by the latch 2°). When a power interruption is detected, microprocessor 201
The motion signal is transmitted through A converters 212, 214 and stepper servo and driver 216 to stepper motor 86 to automatically pull read/write head 48 onto landing pad 96. Power to control the automatic retraction of head 48 is derived from spindle motor 37, which acts as a generator (as detailed above). Then, the signal is sent from the automatic backward force supply section 230 to the spindle servo 20.
4 via microprocessor 201.4. D/A converter 212.2, and stepper servo and driver 216. The automatic retract function occurs when a retract signal (such as from switch 108 actuated by latch 20) is accepted by microprocessor 201.

Another advanced embodiment of the invention is shown in FIGS. 6-13. This advanced unit is housed in a housing as described with respect to FIG.

6, 7A, 7B, and 8, details of the advanced magnetic disk unit of the present invention are shown. A pair of magnetic disks 324 (per se known in the art) are mounted on a rotating plate or table 326 that is attached to a rotary drive spindle 328 . Spindle 328 is mounted and supported in bearings 330,332. Spindle 328 is a separate member from table 326;
It consists of a steel plate portion 328(a) and a steel shaft portion 328(b). Table 326 has three screws 329 that are sunk head-first into table 326 and extend into plate portion 328(b).
is attached to the drive spindle 328 by. The magnetic disk 324 is attached to the rotary table 3 by a top plate 334 that is removably attached to the table 326 by screws 336 and a ring spacer 335 between the two disks.
It is locked on 26. As best seen in FIG. 7A, the top plate 334 overlaps the inner edge of the central opening of the upper disk 324 to lock the disk to the table 326. The table 326 is driven by a motor 337 whose stator 338 is mounted to a housing member 340 and whose rotor 342 is mounted to a skirt 344 attached to the rotary table 326. Electric power is the motor 33
7, table 326 and disk 324
rotates clockwise or counterclockwise as desired, preferably clockwise relative to the rotating arm system of this embodiment. Clockwise rotation of the disk for the rotating arm system provides good stability of the head over small torsional angles as the head flies over the disk.

The housing member 340 has a screw 341(a).

It consists of upper and lower segments 340 (a), 340 (b) attached by 341 (b). screw 341
(a), 341 (b) each have multiple numbers,
The screws 341 (a) and 341 (b) are the main body 3I2
The member 340 is extended to the thick part of the base of the main body 312.
Attach to. The bearings 330, 332 are connected to the annular flanges 3 of the segments 340 (a), 340 (b), respectively.
43 (a) and 343 (b).

The rotary table, drive spindle, and related structure of FIG. 6A includes important features of the present invention for improved vibration and temperature characteristics. The magnetic disk 324 is made of aluminum. Drive tables, such as table 326, are typically made from steel.

However, somewhat surprisingly, aluminum disk 32
4 on a steel drive table, it has been found that there is a problem of differential expansion with temperature.

The occurrence of this problem was unexpected and should be avoided since thermal expansion was expected to be isotropic (ie, uniform) with respect to the axis of spindle 328. However, this proved not to be the case in this case. Rather, it has been found that thermal expansion begins at each clamp location where disk 324 is clamped to table 326. As a result, anisotropic (non-uniform) thermal expansion occurs, and this problem arises because the coefficients of thermal expansion of steel and aluminum are very different (1
/3), the problem is exacerbated by the presence of a steel drive table in the center of the disk 324. As a result of this differential expansion, the central aperture of the disk 324 becomes distorted, severely hampering the operation and reliability of the unit.

According to the present invention, this differential expansion problem is solved by using an aluminum drive table 326, an aluminum l plate 334, an aluminum spacer ring 335, and a screw 336, the aluminum drive table 326 has a cryogenic joint and a screw. 329 to the steel plate portion 328 of the drive spindle
(a) is locked. The mating recesses of the plate 32B(a) and the drive table 326 are sized to be press-fitted.

The cryogenic joint between the aluminum table 326 and plate section 328(a) is constructed by cooling the steel plate 328(a) with liquid nitrogen, heating the aluminum table 326, and then combining these sections and leaving them at room temperature. It is formed by These parts are then locked together. This cryogenic temperature promotes alignment between the sections and helps keep disk 324 coaxial and perpendicular to drive axis 328(a).

Improved vibration characteristics of the drive spindle and rotary table are achieved by preloading the bearing structures (339, 332). The bearings 330, 332 include a central ring spacer 346 and a pair of opposed bellvilles (1) that load the bearings apart from each other and against their support flanges 343(a), 343(b).
springs 348, 350 and are pressed against said flange. Wide temperature range (BTR
) “O” ring 352 connects load plate 354 and lower bearing 33
0, and the load plate 354 is attached to (but spaced apart from) the spindle shaft 328(a) by screws 356. The screw 356 and load plate 354 are adjusted to apply a 20 bond preload to the "O" ring 352, which is also applied to the bearing packs (330, 332). This preload, working in conjunction with the Belville spring, maintains contact throughout the bearing pack to reduce the effects of shock loads and vibrations.

With reference to FIG. 7B, important details of the invention are shown.

The screw 356 connects the hole 3 into which a spring 360 and a ball 362 (all of steel or other conductive material) are placed.
It has 58. Spring 360 forces ball 362 against metal housing 321, thus grounding spindle 328 and table 326 to housing 312, avoiding static charge or voltage build-up.

The continuation write head mechanism 366 is connected to the upper and lower magnetic disks 32.
4 (both sides of which can contain data). The read/write head mechanisms are the same and only one of them will be described. The read/write mechanism is shown generally in FIGS. 6 and 7A and in detail in FIGS. 9A and 9B. The read/write head mechanism 366 includes a magnetic pickup head 37 mounted at the end of a contoured beam 370.
01 and a bending member 371 attached to the end of the beam 370. Beam 370 is attached to a support plate 372, which in turn is attached to a mounting platform 374 of rotating arm 376. beam 3
70 and bending member 371 hold the head 368 above but out of contact with the disk 324 when the unit is in operation, and the beam 370 flexes to move the head 368 between the home and operating positions. The head 368 is raised and lowered when going back and forth between the two, and this will be described in detail later.

In the embodiment of Figures 1-5, the read/write mechanism was mounted to the carriage and guide rod for linear movement. Although this structure is suitable for its intended purpose, it presents several problems which are overcome by the embodiments described below. One problem is that linear actuation systems require precise alignment between several guide rods, which requires delicate placement of many bearings in alignment. Also, the length of the unit must be sufficient to accommodate linear motion, resulting in the unit being too long for some applications. The rotating arm system of the following embodiment overcomes these problems.

With particular reference to FIGS. 6 and 8, rotating arm 376 is mounted for rotation on an axis 378 that is integral with triangular foot pad 380. Referring specifically to FIGS. Foot pad 380 is attached to the base of main body 312 by three screws 380. rotating arm 376
is attached to the shaft 378 by a depending integral sleeve 384 held between an upper bearing member 386 and a lower bearing member 388. Lower bearing 388 rests on an annular step 390 of foot pad 380 and an annular flange 392 engages a lower portion of sleeve 384. An annular flange 394 of upper bearing 386 engages the top of sleeve 384. A retaining cap 396 is connected to the shaft 378 by screws 398 and a preload "O" ring 400 is retained between the cap 396 and the upper bearing member 386. cap 39
6 and screw 398 preload the "O" ring 400 to prevent the elements of bearing 386, 388 and sleeve 384.
to stabilize them and arms 376 against shock loads and vibrations.

It is important that arm 376 be statically and dynamically balanced and have a resonant frequency of 600 Hz or higher. Reinforcement arms or ribs 402 extend along the upper and lower sides of arm 376, respectively, so that arm 376 is reinforced to meet desired frequency requirements. For static balance, a counterweight 406 is attached to the sleeve 384, and for dynamic balance, the arm 376 is provided with a plurality of counterbalance holes (eg, threaded holes) that allow the weight to be attached and moved. equilibrium can be obtained.

The read/write head 368 can be dynamically balanced about its x, y, and z axes (see Figure 9B). This can be accomplished by forming the head 368 with weight bars 368 (i), 368 (c), 368 (e) forming a mounting channel 368 (C) therebetween;
8 is a channel 368 whose center of gravity in at least the X and Y axes (and preferably also the Z axis) is at the point of attachment 410 of the bending member 371 to the head 368.
It is made into the shape shown in the plane (c). The center of gravity in the Z axis is located as close as possible to the attachment point. Head member 368 has two rails 411 forming an air support surface in a known manner.

The balance of arm 376 and head 368 is an important feature that protects the surface of disk 324 from damage during operation of the unit. During normal operation, the head 368 is positioned above the rotating disk 324 and is held slightly (approximately 10-14 microns) away from the disk by air support effects. Any contact between head 368 and disk 324 during operation will damage the head, the disk, or both. Therefore, such contact must be avoided. The balance of head 368 and arms 376 prevents (or at least reduces) such contact and damage. By mounting head 368 at its center of gravity in three axes, the rYJ axis (i.e., the axis along beam 370)
Eliminate or reduce head turnover around. The elimination of rolling motion reduces the risk of the head contacting the disk as it moves from one position to another with respect to the disk. Rolling also creates the risk of the head contacting the disk due to vibrations, and eliminating rolling also reduces this risk.

Rotating arm 376 is driven by a stepper motor and pulley and drive belt system. However, arm 376
The driving of the rotary shaft 378 is not simply performed by human power applied to the rotating shaft 378. That is, to improve the accuracy and reduce vibration of the stepper motor drive system, the arm 376 is attached to and driven by the belt system at a location near the end of the arm removed from the shaft 378.

The stepper motor and pulley and drive belt system is best understood with reference to FIGS. 6, 8, and 11. The stepper motor 4I2 (commercially available unit) uses a capscun or pulley 4
16 is attached to the output shaft 414. Pulley 416 connects to a second and larger diameter rotatable pulley 420
A pliable continuous belt 418 (preferably made of polyamide such as Kapton, available from DuPont) engages and drives the belt. There is a ratio of 2/l between the diameters of pulleys 420 and 416. Pulley 420 has a smaller diameter pulley segment 422 attached to a second and specially shaped drive belt 424 .

Drive belt 424 is shown in Figures 10A and 10B. The drive belt 424 is a split belt made of a metal material (preferably stainless steel). The belt 424 is
First single strand section 426 and intermediate space 4
32 has a second double strand section of strands 428,430 forming. In operation, single strand section 426 moves within space 432 between strands 428,430. The belt 424 is tack welded to a pair of mounting studs 434,436, each of which has a threaded central hole 43.
4(a), 436(a).

Belt 424 also has reinforced attachment openings 438 in webs 440 that join strands 428, 430 to strands 426.

Belt 424 is attached to and drives arm 376 and is attached to and driven by stud 434.
．． Arm 3 at 436 and site 438
This is done by the lower wing member 442 of 76. 1st
Regarding Figure 0A and Figure 11, the stud 434 is located at point rAJ.
Attached to arm 376 at , the dual strand portion of the belt (ie, strands 428, 430) is wrapped around right side portion 442(a) of wing member 442 and around small diameter pulley segment 4220. Belt web 440 is attached to pulley segment 422 at attachment site rBJ by threaded fasteners 439 passing through openings 438. The single strand portion 426 of the belt then extends around the pulley segment 422 and the left portion 442b of the wing segment 442.
) and stud 434 is attached to arm 376 at point "C". Stud 434.43
6 is located on the underside of the arm 376, and is attached to the arm 3 by a screw fastener.
76, the screw fasteners are attached to points rAJ, rcJ
It passes through the arm 376 and engages the threaded holes 434(a) and 436(2) of the studs 434 and 436, respectively. As can be seen from the above, the steel belt 424 is attached to the wing 442.
and pulley 422, with the double strand portion of the belt extending from attachment site rAJ to attachment site rBJ, and the single strand portion of the belt extending from attachment site rBJ to attachment site "C"; It passes through the opening 432 in the double strand section.

Wing 442 includes a tensioning mechanism for applying a tension load to belt 424 and keeping belt 424 taut in contact with the surfaces of wing 442 and pulley 422. The tension load is applied to the end of wing portion 442(b) which is split (i.e. separated from wing 442(b)) and forced outwardly onto belt strand 426 by spring 446 housed in hole 448 in wing segment 442(a). Provided by segment 444. A pair of guide dowelbins 450
(only one of which is visible in FIG. 11) is press fit into tension segment 444, and wing 442(a)
It is slidably fitted into a pair of holes 452 . The dowel pins help keep the tension segments 444 in alignment with the main body of the wing, and the springs 446 push the segments 444 outwardly to impose a tension load on the belt 424. It is important to note that the split belt was previously used to convert rotational motion into linear motion, and the split belt is used in this example to convert rotational motion into rotary motion. Further, in the present invention, belt 424 is operated by direct 100% positive drive of arm 376, rather than relying on frictional drive.

This positive drive increases the positioning accuracy of arm 376.

Stepper motor 412 moves arm 376 in small steps in response to actuation signals sent thereto.

When the stepper motor is actuated, pulley 416 is moved in steps in a circular motion to move bell 418 and pulleys 420, 422 in corresponding steps in a linear and circular motion, respectively. Since the ratio of the diameters of the pulleys 420.416 is 2/1, the drive step of the pulley 420.422 is only 1/2 of the drive step of the pulley 416;
This system thus has a built-in ratio of I/2.

Movement of pulley 420 drives split belt 424, which feeds single strand section 426 through double strand section space 432 and forces arm 376 clockwise or counterclockwise about the axis of shaft 378. Move in stages. In fact, because it is desirable to move arm 376 intermittently by very small amounts (due to the spacing of the data bands on disk 324), the output of stepper motor 412, and therefore also the movement of arm 376, depends on the opposing coils of the stepper motor. micro-stepping by use of well-known micro-stepping drive techniques employing .

Similarly to the first embodiment (Fig. 1-5), the stepper motor 4
12 places the read/write head 368 in the desired position with respect to the disk 324. A head 368 drives the disk 32 for reading or writing.
When in the upper operating position of 4, the head is close to the disk but away from it, and the head 36 is moved to avoid contact with the disk to avoid damaging the disk.
It is important to keep the 8 spaced apart from the disc. When the disk is rotating, an air cushion or air support effect is established between the disk 324 and the head 368, causing the head 368 to operate like a flying head. However, when the disk 324 is not rotating (or when head retraction is programmed), the head 368 retracts to a "home" or "reference" position, in which the head retracts and protects the head. It is stored on a pullulan (acetal polymer) landing pad 454. If the disk rotation stops for any reason, the stepper motor 412 is activated by the read/write head 368.
The belt 418 is driven in a direction that moves the belt 418 away from the disk 324. When the head assembly is retracted, the bending beam 370
The lower cam follower 456 (the cam follower 456 is a spherical or hemispherical ball element) contacts the leading edge 458 of the membrane element 460, which causes the head 368 to be lifted off the disk 324 (i.e., the cam follower 456 is a spherical or hemispherical ball element). ). The spherical or hemispherical cam follower 456 has the necessary rapid angular changes to raise and lower the head 368 quickly over relatively short linear distances. Further retraction causes read/write mechanism and head 368
moves parallel to the disk 324 (with the head 368 spaced apart from the disk), the cam follower 456 then drops behind the trailing edge 462 of the step 460, and the head 368 returns to its rest position on the Teflon landing pad 454. Descend. Similarly, a signal is sent to the stepper motor 412 to move the read/write mechanism to the operating position and position the head 368 above the disk 324, causing the ball cam follower 456 to
62 and lift the head 368 off the landing pad 454. The read/write mechanism and head 368 then move parallel to the disk 324 with the head 368 spaced well above the disk 324. Ball cam follower 456 then falls along trailing edge 458 of step 460, lowering head 368 to an operating position away from the plane of disk 324. This movement of the head 368 perpendicular to the disk 324 as the head 368 moves to the retracted or operating position is a very important feature of the present invention and prevents head dragging across the surface of the disk.
This protects both the head and disk.

It is important to note that the mechanism for raising and lowering the head is small and simple. This allows the raising or lowering movement to take up a short space and cover a short transition of the arm 376, which is an important space-saving feature in a system where space is at a premium.

The ball cam mechanism also causes the head 368 to rise or fall rapidly, which reduces the disk and head from vibration damage when the air support effect is lost. If the unit is stopped for any reason during operation of the unit, the air support effect is lost to the air velocity and it is important to remove the head from the disk as quickly as possible to avoid head flapping or tipping. For the same reason, when the head is lowered into the operating position, it is desirable to lower it as quickly as possible. A ball-shaped cam follower and step cam accomplish these objectives. And the balanced head shape (described with respect to FIG. 9B) also reduces shuffling or flapping during head raising or lowering.

Although only one landing pad and cam mechanism has been described, it will be appreciated that each of the four beams 366 has a cam follower 456. Also, for each beam 36G there are four landing pad stacks and cam mechanisms arranged in a straight line.

Similar to the linear unit described above, the rotary arm mechanism includes an electro-optic sensor 464 that functions to deactivate the stepper motor when arm 376 and head 368 reach a fully retracted position. Flag 4 on arm 376
66 is attached. When arm 376 reaches the fully retracted position, flag 466 enters the slit in sensor 464. When arm 376 and hept 368 reach the fully retracted position, flag 466 interrupts the optical path of sensor 464, causing sensor 464 to generate a signal that terminates operation of stepper motor 412 in the retract direction.

Similar to the linear unit described above, the rotary arm embodiment includes a harmonic system such as that shown in and described in FIG. 1, in which the zero magnetic sensor 116
interacts with the skirt 44 to sense the index notch 118 or other indicator on the skirt 44 to determine the "O" position and coordinate the angular position of the disk with the axial movement of the head 48.

Skirt 44 is comprised of a magnetic material such as iron.

Index notch 118 is actually magnetic iron skirt 44
This is the air gap. Therefore, the sensor II6 detects the magnetic path (reluctance) in the index notch 118.
Detect changes in In this manner, the angular position of the stored data (and its readout) and the axial position of the head 368 can be coordinated from the reference point to retrieve the desired information.

Similar to the linear unit described above, the rotary arm unit is capable of disabling arm 376 and head 36 if power is interrupted for any reason.
8 moves to a fully retracted position. Power interruption is caused by a normal shutdown command, i.e., an intentional shutdown.
Alternatively, it may occur due to abnormal circumstances such as a power outage, or by actuation of the front cover latch 320 to the open position to remove the unit from its cradle while the disk is rotating. Opening of latch 320 is sensed by a magnetically operated switch 408 on handle 318, FIG. 6, which operates to cut off power to the unit. Regardless of the reason for the power interruption, the voltage to the spindle motor 337 will drop. This voltage drop is caused by the electronic control unit (
5). The still rotating spindle motor then powers the stepper motor and stepper motor microprocessor to drive arm 376 and head 368 to the fully retracted position in the same manner as described for the previous (linear) embodiment. It is used as a generator to provide

Similar to the linear unit described above, the case or housing rotating arm unit is sealed within the cover plate 314 by a channel 309 with a molded seal 3IO1, preferably an elastomeric seal.

The seal 310 is compressed between the cover plate 314 and the housing 3!2 to seal the interior space of the unit.

It will be appreciated that cover plate 314 and housing 312 have alignment holes that accommodate screws I6. (The holes are preferably located outside of seal 310.) The interior of the sealed unit is filled with an inert gas, such as Freon, to establish and maintain a constant atmosphere for the system. The rotational movement of the disc 324 causes a flow or circulation of Freon within the sealed unit, which passes the gas through an internal filter 468 that allows the gas (from the disc or other components within the system) to pass through the internal filter 468. Filter out any contaminants that appear. The combination of sealing and internal filter provides a particularly stable and contaminant-free environment.

As previously indicated, the entire magnetic disk unit is housed in a support cradle. Cradle 470 is No. 12A
12B.

In addition, Fig. 12A, Fig. 12B, Fig. 13A, Fig. 13B
The figure shows the vibration reduction features of the mounting cradle.

The magnetic disk unit is located inside 47 of the cradle 470.
2 and is housed therein. The cradle 470 has a pair of internal asymmetric grooves that engage an asymmetric groove (not shown) in the housing 312 and guide the unit into position within the cradle for engagement with electrical connections (not shown) at the rear of the cradle. It has a guide rail 474. Handle 3
A well-known gearing mechanism in the front cover 318, actuated by 20, locks the binion gears 478, 480 with the toothed rack segments 482, 484, locking the disc unit to the cradle. The gear engages the rack segment and forces the disk unit toward the rear of the cradle against leaf spring 486, thereby reducing front to rear vibration. The front cover, handle, and gear mechanism and basic cradle structure are well known and such as the Model 6400 series tape units available from Raymond Engineering, Inc., the assignee of this application.

Both upper and lower rollers 488 on the upper and lower screen surfaces of the cradle.
The set No. 490 narrows the height of the opening to the cradle so that the cradle roller and both upper and lower surfaces of the disk unit fit together with slight tightness. In that case, the disc unit housing slightly curves outwards on both the top and bottom sides of the cradle, which generates a spring action and force, which further stabilizes the disc unit against vibrations and prevents resonance of the cradle. . The rollers also serve as insertion guides to facilitate insertion of the disk unit housing into the cradle.

Another vibration isolation feature is shown in Figure 13B,
Elastomeric or soft plastic elements 492.49
4 is above and below the gear 478.480 and the front cover 3
It is located at the rear of 18.

Elements 492.494 are connected to rack segments 482°48
4 to further securely attach the component and isolate it from vibration.

Although the preferred embodiment has been illustrated and described, various modifications may be made thereto without departing from the spirit or scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the external casing or housing of the magnetic disk unit of the present invention, FIG. 2 is a top view of the unit of the present invention, with the top cover removed, and FIG. 3 is a top view of the unit of FIG. is a sectional view taken along line A--A in FIG. 2, FIG. 4 is a partial sectional view taken along line 4--4 in FIG. 2, and FIG. FIG. 6 is a top view similar to FIG. 2, showing a second advanced embodiment of the present invention; FIG. 7A is a block diagram of an electronic control system suitable for use in FIG. Partial view taken along the line, No. 7
Figure B is an enlarged view showing details of Figure 7A, Figure 8 is a partial sectional view taken along line 8-8 in Figure 6, Figure 9A is a view showing the read/write carrier used in the present invention, Figure 9B is an enlarged detail view of Figure 9A, and Figure 9C is a view of C of Figure 9A.
10A is a view showing the split belt of the invention; FIG. 10B is an enlarged detail of FIG. 10A;
FIG. 13A is a view of the front cover and locking handle used in the present invention, and FIG. 13B is an enlarged detail view showing features of the cradle/handle. 10. Housing 14. ,, cover plate, +8
．． ,,Front cover, 20. ,,Latch mechanism,24,,,
magnetic disk, 26. ,,table,281. Spindle, 33. ,, Elastomer-based member, 37. ,, motor, 44. ,,skirt, 46. ,, read/write head mechanism, 50°99 bent beam, 54. ,,
Head carriage, 56.58.60. ,,guiding rod, 62. ,. SI Balance Assembly, 800. drive belt, 8
618. Stepping motor, 90. ,, tightening finger, 98. ,,cam follower, 1゜131
．． cam member, 104. ,,sensor, 106,
, flag, +08. ,,magnetic operation switch, ＋
16. ,,Zero index magnetic sensor,118,,,
index cutout, 324. ,. magnetic disk, 326. ,,Table, 3281.
, spindle, 334. , ,Top plate, 335,...
spacer ring, 336. ,,screw,337,,,
motor, 360. ,,spring, 362,,,ball, 366,,,read/write head mechanism, 370
．． ,,beam, 371. ,. Bending member, 376, Rotating arm. FICl, 2A Fi6.9B na UrabeFIG, IZ^

Claims (1)

Claims: 1. A magnetic disk storage unit comprising: a housing means; a disk support means rotatably mounted on the housing means; the disk support means supports at least one magnetic storage disk; drive means within said housing means for rotationally driving said disk support means for housing and holding said disk support means; read/write head means for interacting with a storage disk to be mounted on said disk support means; a rotational support mounted on said housing means. an arm, said read/write head means being mounted on said rotary arm means; a stepper motor mounted on said housing means for driving said rotary support arm means over an arc of transition relative to a magnetic storage disk mounted on said disk support means; means,
The output of this stepper motor means is a successive circular arc motion, and is connected between said support arm and the output side of said stepper motor to rotate said support arm and a read/write head mounted thereon in steps. belt means. 2. The unit of claim 1, wherein the disk support means includes a rotary table made of a first material, the rotary table having a rotationally mounted spindle made of a second material. The table and the spindle are joined by a cryogenic joint. 3. The unit according to claim 3, wherein the rotary table and the spindle have different coefficients of thermal expansion, and the coefficient of thermal expansion of the rotary table is the same as that of the storage disk mounted on the rotary table. is substantially equal to the coefficient of thermal expansion of 4. The unit according to claim 2, wherein the rotary table is made from the same material as the storage disk. 5. The unit according to claim 2, wherein the rotary table is made of aluminum and the spindle is made of steel. 6. A unit according to claim 1, wherein said drive means comprises: a rotating spindle supported on bearing means; and preload means for maintaining said bearing means in an operating position. 7. The unit of claim 6, wherein the preloading means comprises: a preloaded elastomeric "O" ring. 8. The unit according to claim 6, wherein the bearing means includes: spaced apart first and second bearing means for pressing and separating the first and second bearing means; Spring means and means for preloading said "O" ring means. 9. A unit according to claim 1, comprising: grounding means for grounding the disk support means to the housing means; 10. The unit according to claim 9, wherein the disk support means includes a rotary table and a rotary spindle, and the grounding means includes conductive ball means and a connection between the spindle means and the housing. conductive spring means, said spring means urging said ball means against said housing. 11. The unit according to claim 1,
The rotating support arm means includes: an arm; a support shaft; the arm is attached to the support shaft; foot pad means is attached to the housing and supports the support shaft; and the arm and the support shaft are attached to the support shaft. and a bearing means for mounting the arm on the support shaft. 12. The unit of claim 1, wherein the arm has a depending sleeve, the bearing means includes first and second bearings, and a second of the bearings is connected to the first bearing. spaced apart from a bearing, said depending sleeve being held between said first and second bearings, and comprising means for imposing a preload on said bearing and said depending sleeve. 13. The unit of claim 12, wherein the preloading means comprises: an elastomeric "O" ring in contact with the second bearing; and pressing the bearing and sleeve together. means for loading said "O" ring onto said second bearing; 14. The unit according to claim 1,
Reinforcing ribs of said rotating support arm means, including: 15. The unit according to claim 1,
A counterweight attached to said support arm means to provide static balance thereof, comprising: 16. A unit according to claim 15, comprising: attachment means for attaching a weight to the support arm for dynamic balance. 17. The unit according to claim 1,
The read/write head comprises: at least one magnetic pickup head, a bending beam having the magnetic pickup head attached to a first end, and a support plate, the support plate being at a second end of the bending beam. and this support plate is attached to said rotating support arm means. 18. A unit according to claim 17, comprising: means for dynamically balancing said read/write head means. 19. A unit according to claim 18, wherein said means for dynamically balancing said read/write head means comprises: a weight bar on the top surface of said head means, said bars between which said means for dynamically balancing said read/write head means include: forming a mounting channel, said bending beam extending from said rotating arm means and being attached to said head means at said mounting channel. 20. A unit according to claim 19, wherein the center of gravity of the head unit in at least two mutually perpendicular directions lies at the attachment point of the bending member to the head means. 21. A unit according to claim 17, comprising: means for supporting the magnetic head when the read/write head means is in a retracted position; and means for supporting the magnetic head when the read/write head means is in a retracted position; means for raising and lowering said bending beam when moving relative to said means; 22. The unit according to claim 1,
The means for raising and lowering the bending beam includes: a cam follower means of the bending beam, and a step in the means for supporting the magnetic head, the cam follower being in contact with the step and raising and lowering the bending beam. Lower the beam in a second, opposite direction. 23. The unit according to claim 22, wherein the cam follower means is spherical or hemispherical. 24. The unit according to claim 1,
A rotary pulley means is included for connecting the output side of the stepper motor to the split belt means. 25. A unit according to claim 24, comprising: wing means of said rotary support arm means; said split belt means extending between said wing means and said pulley means; 26. The unit of claim 25, wherein the split belt means comprises a first single strand section and a second single strand section.
a double strand section, said double strand section forming an intermediate space between said strands into which a single strand section transitions, said double strand section being attached to and wrapped around one end of said wing means; wrapped around a portion of the pulley means, the single strand section being wrapped around a portion of the pulley means and extending through the space of the double strand section and around a second end of the wing means; can be attached to. 27. A unit according to claim 26, comprising means for applying tension to the split belt means. 28. The unit of claim 27, wherein the tensioning means comprises: a split end segment at one end of the wing means; spring means for applying a tension load to said split belt means; 29. A unit according to claim 28, comprising: alignment means for keeping said split end segment in alignment with said one end of said wing means. 30. A unit according to claim 1, wherein said housing means is sealed. 31. The unit of claim 30, comprising: an inert gas within the sealed housing. 32. A unit according to claim 31, comprising: filter means in said housing means for filtering said inert gas. 33. The unit according to claim 1,
an electro-optic sensor in said housing means for generating an optical path, interrupting said optical path of said electro-optic sensor means when said rotating support arm means and said read/write head means are in a retracted position; Flag means in said rotatable support arm means thereby causing said electro-optic sensor means to generate an output signal terminating operation of said stepper motor means. 34. The unit of claim 1, wherein the disk support means includes a skirt, the skirt is made of magnetic material, and the skirt has a predetermined gap forming an index notch, The unit further includes: zero-index magnetic sensor means for interacting with the skirt to sense changes in the magnetic path in the index notch. 35. The unit according to claim 1,
latching means on the outside of said housing means for locking and unlocking said housing means into a cradle containing said housing means, and said latching means being actuated by cooperation with said latching means; switch means for cutting off power to said unit when 36. The unit according to claim 1,
converting said disk support means drive means into a power generator to produce electrical power to drive said stepper motor, thereby controlling said rotary support arm means and said read/write upon interruption of power to said unit; Means adapted to move the head means to a retracted position. 37. The unit according to claim 1,
Mounting cradle means for accommodating said housing means; roller means in said cradle means for establishing an interference fit between upper and lower surfaces of said housing means and said mounting cradle. 38. The unit of claim 37, further comprising: means for locking said housing means to said cradle;
and leaf spring means of said mounting cradle, said locking means pressing said housing means against said leaf spring means. 39. A unit according to claim 37, comprising: elastomeric shock absorbing means between the housing and the cradle.