JPH08171783A - Method and apparatus for launching and retraction of read-write head with reference to medium of disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize clash between a read/write head and a recordign medium, and thereby to improve the reliability of a disk drive by employing one mechanism for launching/retraction of the read/write head. SOLUTION: The mechanism includes a retract lever 81, a retract lever lock 118, a mechanical biasing member (spring 76 or the like), and a voice coil motor 16. After launching, the voice coil motor 16 is used to rotate the retract lever 91 to increase the potential energy of the biasing member. Then the retract lever lock 118 is used to store the built-up potential energy. On the occurrence of a power failure of the disk drive, the mechanism retracts the read/write heads 55, 58 automatically from the medium. The stored mechanical energy during the retract motion of the read/write heads 55, 58 acts on the retract lever 91 to allow the read/write heads 55, 58 automatically to be retracted from the medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive, and more particularly to a method and apparatus for launching or retracting a head in a disk drive.
The invention can be used in fixed disk drives or floppy disk drives that use fixed or removable media.

[0002]

In the early and mid 1970s,
Almost all drives used removable media. However, many drives have used fixed media since the early 1970s. In these fixed media drives, there was little problem with removing the head from near the media when access to the data became unnecessary. Recently, there is a tendency to return to removable media. This trend has revived the issue of read / write head launching and retracting.

Removable cartridge disk drives must be capable of accurately, smoothly, and efficiently loading the read / write head onto the media generally protected within the disk cartridge. Further, it is desirable for the head to be removable from the media when the operator intentionally terminates the use of the cartridge in the drive, or when the drive encounters an unexpected power loss during its use. If the read / write head is seated on the disk surface when the motor stops rotating due to power loss, the head is left on the drive for a long time before the drive power is restored. May cause the disc to stick. This phenomenon is known as stiction. Furthermore, if the read / write head is placed on the disk surface, it will be damaged during the transfer of the disk. Therefore, it is desirable that the head be automatically removed from the cartridge without damaging the head or the storage medium being processed whenever the power supply to the drive is cut off.

In the past, various methods have been employed to control the power-on and power-off of the pulling of the head from the medium. Many prior art drives allow the cartridge to be removed in the event of a power loss, generally without damaging the recording medium, the read / write head, or both, and without the associated risk of data loss. It is very difficult to remove the cartridge from the drive as well as to pull the read / write head from the medium, which is required in advance.

In the past, various methods have also been used to control head launching in disk drives that employ removable disk cartridges. For example, US Pat. No. 4,870, issued Sep. 26, 1989 and assigned to the assignee of the present application.
No. 518 proposes two different methods used to control head launching speed in a removable cartridge disk drive. One of the methods disclosed in this patent employs a dashpot or air damper to control the launch speed of the read / write head. However, the use of precision air dampers adds to the cost of the drive and these dampers do not automatically remove the head in the event of a power loss.

Other prior art drives use feedback emf (electromotive force) from the head actuator assembly or velocity feedback based on tachometer data. Such drives monitor the speed of the read / write head during the launching process.
Feedback emf generated by the movement of the actuator
An example of controlling the head launch speed using the is disclosed in U.S. Pat. No. 4,864,437 assigned to the assignee of the present invention. Also, the use of these devices adds to the cost of the drive and does not lend itself to automatic head removal after the drive loses power. Also, during low speed operation, for example during loading of the read / write head, feedback e
It is difficult to accurately detect mf.

Conventional methods of controlling the launch rate of read / write heads are complex and increase the likelihood of drive failure. In addition, these prior art devices are costly to implement in a drive.

Therefore, the speed of the actuator is controlled during the launch of the head, the speed of the actuator is controlled during the retraction of the head, and sufficient energy is stored to automatically retract the read / write head when the power is lost. There is a current need for better ways to do this.

[0009]

Accordingly, it is a general object of the present invention to provide an improved method and apparatus within a disk drive for launching and retracting read / write heads, where the foregoing is described. The problems and drawbacks of (1) are taken into account and reduced.

Another object of the present invention is to use the electromotive force (emf) generated in the coil of the actuator motor to gradually increase the tension of the retracting spring and the friction of the guide surface of the head unload arm. It is an object of the present invention to provide a read / write head launching device that allows speed control of the head arm assembly during balancing and launch.

Another object of the present invention is to provide a read / write head retractor that uses energy other than electrical energy to remove the read / write head from the disk surface whenever power loss occurs to the drive.

Still another object of the present invention is to be able to automatically retract the read / write head upon loss of power to the drive, thereby lifting the head from the disk surface without damaging the read / write head or the disk or both. It is an object of the present invention to provide a read / write head launching and retracting device.
Therefore, a phenomenon called sticktion when the head is lifted from the disk surface is also eliminated.

[0013]

To achieve the above and other objects of the present invention, an apparatus is provided for launching a read / write head on a disk in a disk drive and retracting the read / write head from the disk. . The disc may be mounted in a cartridge. The device includes a read / write head, a pivotally mounted retracting lever and a mechanical biasing member (e.g., a spring), the read / write head is attached to the head arm assembly, and the retracting lever has a pressure end and a trappable end. The retracting lever is positioned such that the pressure end of the lever is adjacent to the pressure surface of the head arm assembly and the mechanical biasing member applies the pressure end of the lever to the pressure surface of the head arm assembly. Energize. In the preferred embodiment, a sleeve of energy absorbing material is attached to the pressure end of the retracting lever. Retractor lever locks are provided to alternately trap and release the trappable ends of the retractor levers,
A solenoid is attached to the retract lever lock to position the retract lever lock. A voice coil motor is operatively associated with the head arm assembly and is used both to launch the read / write head and to position the read / write head to write data to or read data from the disk. The apparatus also includes a head unload arm consisting of a fork-shaped portion having an upper guide surface and a lower guide surface.

Other objects, effects and features of the present invention will become more apparent to those skilled in the art by studying the following description and attached drawings.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a disk drive device is provided for launching a read / write head on a disk and retracting the read / write head from the disk. In the preferred embodiment, one disc is contained in the cartridge. However, the invention is not so limited and will also apply to multiple discs and discs not mounted in a cartridge. In the following description, if component A is described as being provided on top of component B, this means that component A is from drive base 10 (eg, the bottom in the drive) rather than component B ( It means further away (in the direction away from the paper surface of FIGS. 1 to 8).

First, referring to FIGS. 1 to 8, the disk drive device of the present invention includes the following components. The head arm frame 13 is mounted on the drive base 10. Positioning motors for voice coil motors (VCMs) or head arm assemblies are typically 16
Indicated by. The head arm assembly 19 includes a head arm frame 1 so that the head arm assembly 19 can rotate about an axis 22.
3 is pivotally mounted. The inner crash stop 25 is mounted on the voice coil motor 16 and the stop pin bumper 28 abuts the stop pin 34 of the inner crash stop 25 when the head arm assembly 19 is rotated to the innermost position on the medium 37. And the stop pin bumper 28 is formed of energy absorbing rubber and is mounted on the base end 31 of the head arm assembly 19. In the preferred embodiment, the stop pin 34 is threaded so that its position in contact with the stop pin bumper 28 is adjusted.

The head arm assembly 19 consists of a bifurcated load beam 40, which includes an upper load beam 43 and a lower load beam 46 (FIG. 10). The head arm assembly 19 further includes an upper flexure 49 attached to the upper load beam 43 and a lower flexure 52 attached to the lower load beam 46.
Consists of A pair of transducers (read / write heads) 55, 58 are mounted on the free ends of flexures 49, 52. The upper read / write head 55 is attached to the upper flexure 49 by a gimble (not shown). The lower read / write head 58 is attached to the lower flexure 52 by a jimble (not shown). These features are best seen in FIG. In this preferred embodiment, the pressure surface 61
Consists of a molded ratchet 64 which is rotatably mounted below the head arm assembly 19. The blade 67 depicted on the ratchet 64 is not used in this preferred embodiment.

Next, the retracting spring and the retracting spring hook will be described with reference to FIGS. 1 to 8, 11 and 12. Retracting spring hook 70 is ratchet 6
4 is mounted on the drive base 10 adjacent to the operation area 4. Retraction spring hook 70 has a slot 73 formed to adjust the initial tension of retraction spring 76. In the preferred embodiment of the present invention, retraction spring 76 has a spring modulus of 16 ounces per inch. The retraction spring hook 70 will be rotated about the mount screw 79 to adjust the initial tension of the retraction spring 76. The second mount screw 82 rides in the slot 73, which limits the range of motion of the retractable spring hook 70. When the initial tension of the retracting spring 76 is adjusted, the retracting spring hook 70 is fixed to the drive base 10 by tightening the mounting screws 79 and 82. Retractable spring hook 70 includes a vertical portion 85, which has a spring retaining groove 88 formed therein (FIG. 12).

Next, the pull-in lever 91 will be described with reference to FIGS. 1 to 8, 13 and 14. Retracting lever 91
Drive base 10 so that it can rotate about axis 94.
It is rotatably mounted on. The pull-in lever 91 is located below the head arm assembly 19 and has its shaft 94.
Mounted on. This is the retractable lever 9 when covered by the head arm assembly 19.
1 to 8 by drawing the hidden portion of 1 by a virtual line
Is shown in. The retracting lever 91 includes a pressure end 97. The pressure end 97 of the pull-in lever 91 contacts the pressure surface 61 of the ratchet 64 many times during operation of the disk drive.

A sleeve 100 of cushioning material (eg, energy absorbing rubber) is mounted on the pressure end 97 of the retraction lever 91 in the preferred embodiment. In this sleeve 100, the pressing end 97 of the retracting lever 91 abuts the pressing surface 61 of the head arm assembly 19 to guide the upper and lower flexures 49, 52 to the upper and lower guides 109 of the fork upper part 109 of the head unload arm 112. It mitigates the tendency of read / write heads 55, 58 to crash against the disk when riding over surfaces 103, 106. Read / write head 55, 58
It is important to avoid crashing into the media 37, especially when the media exhibits high density data. The head unload arm 112 is described further below and will best be seen in FIGS. 9, 10 and 15-17.

The retracting lever 91 also has a trappable end 115. The trappable end 115 is a retractable lever lock 1 during normal operation of the disk drive.
It is locked or held by 18. The retracting lever lock 118 is described more fully below and is shown in FIGS.
Will be best shown at 0. The trappable end 115 of the retracting lever 91 has a sloped surface 121, which facilitates the trapping action, as further explained below.

During part of the operation of the head launching device of the present invention, the retracting lever lock 118 presses against the wings 124 forming part of the retracting lever 91. In particular, the bottom surface 130 of the retractable lever lock 118
The push pin 127 mounted on the retraction lever 9 is
Retractable lever lock 11 determined by the degree of rotation of 1
A rotation of 8 will abut the wings 124.
In particular, during the initial portion of the drive's headloading operation (FIG. 2), the push pin 127 causes the retracting lever 91 to rotate and between the compressing end 97 of the retracting lever 91 and the pressing surface 61 of the ratchet 64. Form a gap. The head load operation of the drive will be described later. Retraction lever 91 includes a hole 133, which is used as a fixed point for retraction spring 76.

Head load assembly base 136
The components attached to the will be described in detail. Essentially formed on the head load assembly base 136 is an upper projection 139. This upper projection 139 would best appear in FIG. 21 shows a head load assembly base 1 in the direction indicated by reference numeral 21 in FIG.
36 shows an end elevational view of 36. FIG. Upper projection 139
Operates as a stop of the head unload arm 112. The upper projection 139, which will be described more fully below, allows the head unload arm 112 to
Limit the rearmost movement of. In addition, the first pin 142 and the second pin 145 are connected to the head load assembly base 13.
It is mounted on 6. The first pin 142 operates as a rotation shaft of the extraction lever lock 118 and the head unload arm 112. The second pin 145 rides on the curved portion 148 during rotation of the extraction lever lock 118. The curved portion 148 thereby limits the rotational tolerance of the extraction lever lock 118. Figure 18 shows the extraction lever lock.
~ Best depicted in Figure 20.

The extraction lever lock 118 is connected to the solenoid 151. As shown in FIGS. 1 to 8 and 24, the solenoid 151 is characterized in that it is returned to the inactive position by a spring. That is, when the power supply to the solenoid 151 is stopped,
Central shaft of solenoid 151 or plunger 15
4 extends fully to its inactive position. FIG. 24 shows FIG.
3 shows a side view of solenoid 151 from the direction indicated by reference numeral 24 in FIG. Extraction lever lock 11
A connecting pin 157 is swingably connected to the plunger 154 of the solenoid 151 (FIG. 24). The solenoid 151 produces a force that rotatably positions the extraction lever lock 118. Thus, solenoid 151 provides the energy to operate the drivelock mechanism, which stores mechanical energy that aids in the automatic withdrawal of read / write heads 55, 58 when power is removed from the disk drive. The extraction lever lock 118 also includes a trap pin 160. The trap pin 160 is the extraction lever lock 118.
From the bottom surface 130 of the. This pin 160, which will be described further below, is used to trap the trappable end 115 of the extraction lever 91. Figure 7
And FIG. 8 shows the trap pin 160 performing its trap function.

Now, the head unload arm 112 will be described with reference to FIGS. 9, 10, and 15 to 17.
The head unload arm 112 has a first pin 142 (the pin 142 is depicted, for example, in FIGS. 1-8 and 21).
Mounted on top of the withdrawal lever lock 118 so that it can rotate around, the head unload arm 112 would be manufactured from a suitable engineering plastic or other structural material. In the preferred embodiment of the invention, the material between the guide surfaces 103, 106 above and below the head unload arm 112 has been removed to serve the disk 37 when loaded into the drive. This would best appear in FIG. Therefore, the head unload arm 112 includes a fork-shaped portion 109. As best shown in FIGS. 9 and 10, each guide surface 103, 106 of the forked portion 109 of the head unload arm 112 is flat.
It is in the form of a tapered ramp, with a knee between each ramp or tapered section and its respective flat section. In particular, referring to FIG. 9, the upper guide surface 103 has an upper knee 169.
Lamp part 104 and flat part 1 separated by
It consists of 05. Similarly, the lower guide surface 106 comprises a ramp portion 107 and a flat portion 108 separated by a lower knee 170. This flat taper design efficiently lifts each read / write head 55, 58 from its operating position near the disk surface to its retracted position safely away from the disk surface. When the head arm assembly 19 is fully retracted, the flexure 4 above and below the head arm assembly 19
9 and 52 are upper and lower flat portions 105 and 1, respectively.
It is made to ride on 08. Flat parts 105, 10
8 is the flexure 4 when the cartridge is loaded
The guide surface 103 serves to minimize the vertical movement of the 9, 52 and also provides a surface parallel to the plane of the flexures 49, 52 when the read / write heads 55, 58 are sufficiently resting on the flat portions 105, 108. , 106 to a minimum. Further, the head unload arm 112 includes the lower projection 163 and the bumper mount 16.
Including 6.

During the rotation of the head unload arm 112,
The free end of the head unload arm 112 slidably stops on the head unload arm guide 172. This head unload arm guide 172 is shown in FIGS.
As depicted in FIGS. 8, 10, 22 and 23, the head unloading arm itself may be made of a suitable material, such as plastic. The guide 172 is rigidly mounted on the head load assembly base 136. The coil spring 175 (FIG. 10) is a lower projection 163 of the head unload arm 112.
Is urged toward the stop surface 178 of the head unload arm guide 172. The coil spring 175 includes the head unload arm 112 and the extraction lever lock 11
8 is mounted around the first pin 142. The distance between the stop surface 178 of the head unload arm guide 172 and the upper projection 139 is determined by the full range of possible positions of the head unload arm 112.

The bumper 181 of energy absorbing material (eg, energy absorbing rubber) is the bumper mount 16
Mounted around 6. Bumper 181 is cylindrical in the preferred embodiment and helps to reduce the tendency of head arm assembly 19 to bounce when read / write heads 55, 58 are retracted from the surface of disk 37. In addition, the coil spring 17
5 serves to dampen the collision between the head arm assembly 19 and the head unload arm 112. Coil spring 175 and bumper 181 alleviate the high speed rebound problem that occurs when head arm assembly 19 moves to its retracted position under the influence of retraction spring 76.

1 to 8 are arranged to show the progress of the head launch sequence, starting with the drive until it is powered up, until the read / write heads 55, 58 have fully launched and are in the operational state. ing. In the disclosed invention, one mechanism is the read / write head 5.
It is used for both 5,58 lunch and subsequent withdrawal. The lunch sequence will be described first.

In the head launch sequence, the heads 55, 58 are positioned without position or velocity feedback. In other words, the present invention describes an open loop system. During lunch, the first issue controls the speed of the upper and lower flexures 49, 52, causing the heads 55, 58 to move when the upper and lower flexures 49, 52 leave their respective guide surfaces 103, 106. It is to prevent the medium 37 from crashing. The upper and lower flexures 49, 52 move along their respective guide surfaces 103, 106, in particular the upper and lower flexures 49, 52 taper from the flat portions 105, 108 of the upper and lower guide surfaces 103, 106. Moving toward the portions 104, 107 changes the resultant force acting on the head arm assembly 19. As will be appreciated by considering FIG. 9 and FIG.
Slide down 3 and 106 and read / write head 5
5, 58 move towards each other and towards the medium 37. Head 5 when leaving each guide surface 103, 106
When 5, 58 approach each other very fast, the head 5
5, 58 will crash into the media 37 upon leaving the head unload arm 112. If the read / write heads 55, 58 crash into the medium 37, they will be damaged or they will be damaged by the medium 37, especially the high density medium 37.
The data stored in will be destroyed. On the other hand, when the read / write heads 55, 58 move very slowly toward the medium 37 when they leave the guide surfaces 103, 106 of the head unload arm 112, the heads 55, 58 are clearly separated from the head unload arm 112. Those movements that fly above the medium 37 without breaking away are impaired. This loss is more likely to occur in removable media devices due to the increased vertical protrusion inherent in media replacement.

The step-by-step launching process will now be described with reference to FIGS. 1-8 and 25-27. FIG. 25 shows an algorithm for this process, where the value given is the DAC constant. 26 and 27 show V in part of the launching process.
The current flowing through the CM is shown. In the preferred embodiment of the present invention, the neutral VCM has a DAC value of 80H. 8
Values above 0H apply to forces towards the inner diameter or ID. Values less than 80H apply to the force towards the outer diameter or OD. Torque / DAC count is 7.32 x 10-3 inch-ounce. FIG. 1 shows the launching and retracting device of the present invention with a cartridge inserted into the drive. When the command is issued, the medium 37 rotates. When the medium 37 reaches a predetermined rotation speed, the launch sequence is started.

As shown in FIG. 1, first an OD force is generated to move the flexures 49, 52 to the top of the ramp portions 104, 107 of the upper and lower guide surfaces 103, 106, respectively (step 1 of FIG. 25). ). Next, FIG.
The solenoid 151 is operated as shown in FIG.
Step 2 of 5). When the solenoid is activated, the plunger 154 is retracted into the solenoid 151. When the plunger 154 is retracted, the retractable lever lock 1
18 is pulled, which causes the retracting lever lock 118 to rotate slightly in the first direction (counterclockwise in FIG. 2). This rotation pushes the push pin 127 against the wings 124 of the retractable lever 91. Therefore, the force generated in the wing 124 is the pull-in lever 91.
To rotate slightly about axis 94 (clockwise in FIG. 2). Subsequent rotation of retraction lever 91 creates a gap between the pressure end 97 of retraction lever 91 and the pressure surface 61 of molded ratchet 64.

Next, the electric current of the voice coil motor 16 is dithered (see step 3 in FIG. 25, and also FIG. 26), without excessively accelerating the flexures 49, 52 across the flat portions 105, 108. Flexure 4
Prevents sticktion between the 9,52 and the flat portion 105,108 of the head unload arm 112. This vibration creates a net force that causes the head arm assembly to rotate counterclockwise in FIG. 2 until contact is reintroduced between the pressure end 97 of the pull-in lever 91 and the pressure surface 61. This places the device in the position depicted in FIG. 3 without forming a gap between the retracting lever 91 and the pressure surface 61.

At this point, the upper and lower flexures 49, 52 are aligned with the upper and lower guide surfaces 103,
Migrate each knee 169, 170 of 106 (FIGS. 3 and 9). The flexures 49, 52 stop on the ramp portions 104, 107 of the head unload arm 112 at stop points or preload positions, respectively. In this pre-loaded position, the spring force generated by the retract spring 76 (determined by the position of the retract lever 91, which is the push pin 1 of the retract lever lock 118).
Is rotated by 27 and, as described above, solenoid 151
Voice coil motor 16
The net vibration torque generated by the flexures 49 and 52 does not separate from the preload position (although a small vibration motion occurs around the preload position). Therefore, the location of the preload position is determined by the position of the retract lever 91, which is determined by the setting of the solenoid 151. Solenoid 15
1 is adjusted so that the preload position occurs just after the flexures 49, 52 cross the knees 169, 170 (FIGS. 3 and 9). The vibration time (currently this is about 1.4 seconds) is set so that even in the worst case (adhesive friction), the flexures 49, 52 reach the preload position before the vibration stops. .

FIG. 9 is an enlarged view showing the upper and lower flexures 49 and 52 at the preload position. Figure 9
On the upper and lower guide surfaces 103, 106 on the ramp portions 104, 107 respectively, a flexure 49,
The position of 52 is clearly visible. To this point, the force generated by the retract spring 76 on the retract lever 91 is balanced with the force generated by the solenoid acting on the wings 124 via the push pin 127 of the retract lever lock 118.

After contact is reintroduced between the pressure end 97 of the retracting lever 91 and the pressure surface 61, the voice coil motor 16 has the task of counteracting the force generated by the retracted retracting spring 76. Solenoid 1
Start taking over from 51. The head arm assembly 19 includes a pressure surface 6 of a molded ratchet 64.
It is connected to the retracting lever 91 via 1 and opposes the force generated by the retracting spring 76. Further, when the voice coil motor 16 is driven, the head arm assembly 19 pushes the retracting lever 91 via the pressing surface 61 of the molded ratchet 64,
Pull the retraction spring 76. The emf of the voice coil motor 16 has upper and lower flexures 49, 5
2 is the guide surface 10 of the head unload arm 112
It is progressively increased by the firmware to start moving over the ramp portion 104, 107 of 3, 106. The emf of the voice coil motor 16 is adjustably increased or ramped up at a constant rate of change using techniques apparent to those skilled in the art (see, for example, step 4 of FIG. 25, see FIG. 27). This ramp-up of the voice coil motor emf will pull the retract spring 76 into the motor 1
It will be pulled until it is equal to the force generated by 6. The head arm assembly 19 is then attached to the ramp or slope portion 1 of the guide surface 103, 106.
It travels at a controlled velocity along 04, 107-equal to the Danson-Bar motion-to the disk surface.

When the voice coil motor is simply actuated from the full stop position and the flexure is rotated to move directly over the knee of the head unload arm to the ramp section without stopping in the preload position,
Achieving head speed suppression is very difficult.
This is combined with the unknown load power provided by the flexure moving past the knee of the head unloading arm to utilize the force between the flexure and the guide surface of the head unloading arm to overcome friction and sticktion. , Because it invites flexure acceleration and uncontrolled speed. However, after the flexure reaches the preload position, the current of the voice coil motor is started to ramp up, and the current of the voice coil motor 16 is controlled thereafter, so that the upper and lower flexures 49, 52 are unloaded. Guide surface 1 above and below arm 112
Upon leaving 03, 106, the drive will manage the speed of movement of the read / write heads 55, 58. In this way, when the read / write heads 55, 58 shift from the state in which they are stopped on the fork-shaped portion 109 of the head unload arm 112 to the state in which they are flying over the rotating medium 37, the read / write heads 55, 58, The speed of 58 is controlled so that the heads are closer to each other and to each corresponding disk surface.

During the loading process, the firmware in the microprocessor of the disk drive's electrical circuitry detects the servo data expected to be found on the medium 37 (step 4 in FIG. 25). When the read / write heads 55, 58 start reading servo data from the disk, they are probably fully loaded. In the preferred embodiment, up to 12 steps of voice coil motor 16 ramp-up is used, but the system will normally have heads 55, 58 head unload arm 11 after the sixth ramp-up step.
It is adjusted to leave 2. Read / write head 5
To ensure that 5, 58 actually clears the head unload arm 112, the disk drive firmware uses the flexure 4 after the read / write heads 55, 58 start reading servo data from the disk.
9, 52 are continuously disengaged from the head unload arm 112 (step 5 in FIG. 25). This is because the read / write heads 55 and 58 start reading servo data, and at the same time, the flexures 49 and 52 cause the head unload arm 11 to move.
It happens even if you clear 2 enough.

Next, the solenoid 151 is stopped (see FIG. 2).
5, step 6), the plunger 154 returns to its extended position (FIG. 4). When the plunger 154 returns to its extended position, the retractable lever lock 118 is oriented in the second direction (clockwise in FIG. 4) and the trappable end 115 of the retractable lever 91 is moved by the trap pin 160 of the retractable lever lock 118. It is rotated to a position that allows it to be rotated as a result to a trapped or locked position. This trapping operation is fully explained later with reference to FIGS. 6 and 7.

Next, the current of the voice coil motor 16 is further increased (step 7 in FIG. 25). The increase in the current of the voice coil motor 16 causes the head arm assembly 19 to initially run from the outer track of the medium 37 to the innermost track (see FIG. 5, for example). FIG. 6 shows the head arm assembly 19 in a position beyond the innermost track. When the head arm assembly 19 is in such a position, the stop pin bumper 28 of energy absorbing material abuts the stop pin 34. When the head arm assembly 19 is in this position, the retraction spring 76 is in its most extended state, and the head arm assembly 19 is in the retraction lever 9.
1 is tilted and can be trapped by the retracting lever lock 118. This initial travel of the head arm assembly 19 from the outer track of the media 37 to the innermost track increases the potential energy in the retraction spring 76, thus enabling the drive's automatic head retraction system, while the spring energy retraction lever locks. The retracting lever 91 is placed in the locked position so that it can be stored by 118.

After a short time delay (step 8 in FIG. 25), the solenoid 151 is activated again as shown in FIG. When the solenoid 151 is activated, the plunger 154 is pulled to the left in FIG. This action rotates the retract lever lock 118 in the first direction (counterclockwise direction in FIG. 7) to lock the retract lever 91 in place. When the retractable lever 91 is positioned as shown in FIG. 7, the solenoid 151 is activated and the retractable lever lock 118 allows the retractable lever 91 to be trapped behind a trap pin 160 attached to the bottom of the retractable lever lock 118. The end 115 is trapped, which holds the retraction spring 76 in a tensioned state and stores the potential energy of the spring. In particular, as best shown in FIGS. 18-20, the trap pin 160 presses against the sloped surface 121 of the trappable end 115 of the retracting lever 91. In this state, the trap pin 160 has the pull-in lever 91.
, But is best represented in FIGS. 7 and 8. While the solenoid 151 is operating, the pull-in lever 91 is held in the spring loaded state.

As best shown in FIG. 8, when the retract lever 91 is locked by the retract lever lock 118, the retract spring 76 no longer affects the operation of the head arm assembly 19. The pressure end 97 of the pull-in lever 91 is a ratchet 64 for molding.
The head arm assembly 19 is free to move over the medium 37 without contacting the pressure surface 61 of the. The drive then proceeds to a routine that determines when the drive receives commands from the host computer and prepares to perform the desired read / write operation.

The retraction system of the present invention enables retraction of the read / write heads 55, 58 under normal conditions as well as under power or loss conditions. In normal retract operation, the operator typically initiates the pull-in sequence by pressing a button on the front of the disk drive. The sequence is then initiated by the interface sequence command. After the sequence begins, the read / write heads 55, 58 track the outer track. Accordingly, the voice coil motor 16 provides sufficient force (60H DAC in the preferred embodiment) to move the read / write heads 55, 58 to the ramp portion 10 of the guide surface 103, 106 of the head unload arm 112.
4 or 107 (FIG. 9) is lifted or pushed up to be in the retracted state. The drive is then spun down and the solenoid 151 is substantially stopped, which moves the plunger 154 to the right in FIGS. When the plunger 154 moves to the right, the retractable lever lock 118 is rotated in the second direction (clockwise direction in FIG. 8). Next, the retracting lever lock 118 is moved to the retracting lever 9
Opening the trappable end 115 of No. 1 presses the pressing end 97 of the retracting lever 91 against the pressing surface 61. The retraction spring 76 thereby serves to hold the read / write head 55, 58 on the head unload arm 112 while the cartridge is removed from the drive, for example. In a fixed drive, this feature would be employed before the embedded drive or system was moved.

The retracting of the read / write heads 55 and 58 when the drive encounters an unexpected power loss will be described below. In this situation, the drive's automatic head retract feature is optional. The energy used to unload the read / write heads 55, 58 in this situation is the energy stored in the tensioned retraction spring 76.

In the present invention, the retracting lever lock 118 prevents the retracting lever 91 from affecting the operation of the head arm assembly 19 before a power loss occurs. This locking operation has already been fully explained. As is well known in the art,
Head arm assembly 19 can then be used to access data from tracks on media 37. Solenoid 151 actually relaxes and opens its plunger 154 when the power supply is inadvertently removed from the drive. Open plunger 154
Moves to the right in FIGS. 7 and 8, which causes the retracting lever lock 118 to rotate in a second direction (clockwise in FIGS. 1-8). Thus retracting lever lock 118
When the is rotated, the trap pin 160 moves the retracting lever 9
The one trappable end 115 can no longer be held. The stored energy of retraction spring 76 is consequently released. The energy of the released spring is applied to the retracting lever 91 through the hole 133 of the retracting lever 91 in which the retracting spring 76 is attached to the retracting lever 91. This then causes the retracting lever 91 to rotate in the counterclockwise direction of FIGS. 1-8, and the contact between the pressure end 97 of the retracting lever 91 and the pressure surface 61 of the ratchet 64 actually results. To be done. The force on the pressure surface 61 by the pressure end 97 causes the head arm assembly 19 to rotate in the clockwise direction of FIGS. 1-8, and causes the upper and lower flexures 49, 52 to move respectively to the upper and lower guide surfaces 103, By pushing to 106, the head arm assembly 19 is mounted on the head unload arm 112. Thus, when the drive loses power, the device retracts the read / write heads 55, 58 independent of the placement of the head arm assembly 19 on the media 37, and the read / write head 5
5, 58 is placed safely away from the media 37.

Between the pressure surface 97 of the retraction lever 91 and the pressure surface 61 of the molded ratchet 64 when the head arm assembly 19 is approaching the outer track of the medium 37 as shown in FIG. Has the largest gap. If the drive encounters an unexpected power loss when the head arm assembly 19 is in such a position, the pressure end 97 will have its maximum distance and in between will accelerate towards the pressure surface 61. In this situation, the sleeve 100 of dump material serves to reduce the bounce height of the retraction lever 91 after its pressure end 97 abuts the pressure surface 61. Instead of the sleeve 100, the retracting lever 91 itself may be constructed of a material or shape that reduces the bounce height. For example, the retraction lever 91 itself can be formed of an elastic material that provides a bounce when the pressure end 97 abuts the pressure surface 61.

The above-described invention provides many advantages over the prior art, including the advantages described below. Whenever the drive encounters a power loss, the read / write heads 55, 58 are pulled from the medium 37 using mechanical energy, so the read / write head 5 is always removed when the disk drive loses power.
5, 58 continue to be detached from the medium 37. Read / write heads 55, 5 when the disk drive is not powered
Since the 8 continues to be kept away from the disk surface, the read / write heads 55, 58 will be less damaged than during the movement of the drive in which the disk was loaded. The present invention allows read / write heads 5 to be used without the use of devices similar to dump pots and tachometers or other speed sensors.
Lunch 5, 58. The absence of these devices allows the drive to be manufactured easier and cheaper, while increasing the reliability of the drive.

While the above is a description of the preferred embodiment of the present invention, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit or aspect of the invention. For example, a linear actuator would be used in place of the voice coil motor used in the preferred embodiment. It is intended that all matter contained in the above description and accompanying drawings shall be understood as illustrative and not limiting. Therefore, the present invention is limited only by the appended claims.

[Brief description of drawings]

FIG. 1 is a plan view showing a head launching / retracting device according to a preferred embodiment of the present invention.

FIG. 2 is a plan view showing the next state of FIG. 1 of the device.

FIG. 3 is a plan view showing the next state of FIG. 2 of the device.

FIG. 4 is a plan view showing the next state of FIG. 3 of the device.

5 is a plan view showing the next state of the apparatus shown in FIG.

FIG. 6 is a plan view showing the next state of FIG. 5 of the apparatus.

FIG. 7 is a plan view showing the next state of FIG. 6 of the apparatus.

FIG. 8 is a plan view showing the next state of FIG. 7 of the apparatus.

9 is an enlarged cross-sectional view showing a fork-shaped portion of the head unload arm as a reference for FIGS. 3 and 16. FIG.

FIG. 10 is a perspective view showing a head arm assembly, a voice coil motor, a retracting lever, a retracting spring, a retracting lever lock, a head unload arm, and a head unload arm guide.

FIG. 11 is a plan view showing a retractable spring hook.

FIG. 12 is a side view showing a spring hook in which a spring holding glove formed on a vertical portion is drawn.

FIG. 13 is a plan view showing a retracting lever.

FIG. 14 is a side view of the retracting lever depicted in FIG.

FIG. 15 is a front view showing a head unload arm used in a preferred embodiment of the present invention.

16 is a plan view of the head unload arm depicted in FIG.

17 is a right end view of the head unload arm depicted in FIG.

FIG. 18 is a plan view showing a retracting lever lock.

19 is a cross-sectional view of the retractable lever lock depicted in FIG.

20 is a bottom view of the retractable lever lock depicted in FIGS. 18 and 19. FIG.

21 is a side view of the head unload assembly base seen from the reference direction in FIG. 1. FIG.

FIG. 22 is a plan view of a head unload arm guide.

FIG. 23 is an end view of the head unload arm guide depicted in FIG. 22.

24 is a side view of the solenoid seen from the reference direction in FIG. 1. FIG.

FIG. 25 is a diagram showing a loading algorithm.

FIG. 26 is a diagram showing current applied to a VCM during a vibration phase of a voice coil motor (VCM).

FIG. 27 shows the current applied to the VCM during the ramp up phase of the voice coil motor (VCM).

[Explanation of symbols]

16 voice coil motor 19 head arm assembly 37 medium (disk) 40 load beam 43 upper load beam 46 lower load beam 49,53 flexure 55,58 read / write head 76 retraction spring 91 retraction lever 112 head unload arm 118 retraction lever lock

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jack Duane Sossen Singapore 1025 Balmoral Park, Singapore No. 5 F No. (72) Inventor Duncan Lee Pollock United States 94513 Outrigger Circle, Brentwood, CA, USA 1160th (72) Inventor E Cheok Lo Singapore 2776 No. 71 Apartment Block, Eshan Street, Singapore 720 No. 07-257 (72) Inventor In Ye Cho Malaysia 81750 Jor Bar, Taman Permas Jaya, Jalan Permas 3/4, 104 (72) Inventor Kian Kok Lim Singapore 1750 Singapore, Toh Drive 53

Claims (26)

[Claims] 1. An apparatus in a disk drive for retracting at least one read / write head, comprising at least one disk, mounted to a head arm assembly, from said at least one disk: a pressure end. A retraction lever having a retraction lever arranged to press the pressure end against a pressure surface of the head arm assembly during retraction of the at least one read / write head; A device comprising a biasing member for mechanically biasing a portion against the pressure surface; a retracting lever lock arranged to trap and release the retracting lever. 2. The apparatus of claim 1, wherein the retraction lever further has a trappable end and the retraction lever lock traps and releases the trappable end of the retraction lever. 3. The apparatus of claim 1, further comprising a sleeve of energy absorbing material attached to the pressure end of the retracting lever. 4. The apparatus of claim 1, wherein a solenoid is swingably mounted on the retractable lever lock. 5. The apparatus according to claim 4, further comprising a head unload arm. 6. The apparatus of claim 5 wherein said head unload arm is spring loaded and said head unload arm further has a bumper of energy absorbing material attached thereto. 7. The head unload arm is mounted on the first pin so that the head unload arm can pivot between a frontmost position and a rearmost position, and the head unload arm further includes the head unload arm. 7. The apparatus of claim 6, riding on a head unload arm guide having a stop surface defining a forwardmost position of the load arm, the head unload arm being spring loaded to the rearmost position. 8. The apparatus of claim 5 wherein said head unload arm has a fork shaped portion in the form of a flat taper ramp. 9. (A) at least one disk; (B) (a) at least one flexible member carrying at least one data transducer; and (b) a pressure surface. A head arm assembly; (C) a head cooperating with a ramp surface to support the at least one flexible member away from the at least one disc so that the transducer does not adhere to the at least one disc. Unload arm; (D) retraction lever for storing sufficient potential energy to move the head arm assembly such that each transducer is removed from the at least one disk by the ramp surface; (E) disk Drive de The retractor lever away from the head arm assembly during a data access operation, and the pressure action of the retractor lever against the pressure surface of the head arm assembly prevents the transducer from sticking to the at least one disk. A disk drive having a retracting lever lock for releasing the retracting lever to release the disk. 10. The apparatus of claim 9, wherein the at least one disc comprises a single disc contained in a cartridge. 11. (A) (a) A bifurcated load beam rotatably mounted on a first axis and having an upper load beam and a lower load beam; (b) an upper flexure mounted on the upper load beam; And a lower flexure mounted to the lower load beam; (c) an upper read / write head attached to the upper flexure, and a lower read / write head attached to the lower flexure; and a head including (d) a pressure surface. Arm assembly; (B) (a) Upward projection; (b) 1st pin; (c)
A second pin; (d) a head unload arm guide having a stop surface; (e) a retractable lever lock rotatably mounted on the first pin and including a push pin, a trap pin and a curved port through which the second pin rides. (F) A head unload arm rotatably mounted on the first pin above the pull-in lever lock; (g) Mounted between the pull-in lever lock and the head unload arm, the head unload. A head arm assembly having coil springs for urging the arms toward the stop surface of the head unload arm guide so as to cooperate with each other; (C) rotatably mounted on the second shaft and having a pressure end. A retractable lever having a trappable end and a wing; (D) Between the retractable lever and the retractable spring hook. Linked retraction spring; disk drive with; (E) a solenoid having the retraction lever lock to swingably mounted central shaft or plunger. 12. The head unload arm comprises a portion having an upper guide surface and a lower guide surface, each guide surface having a flat taper shape with a knee between the ramp portion and the flat portion. The listed disk drive. 13. A device for launching and retracting a read / write head attached to a head arm assembly, the device having a pressure end and a trappable end, the pressure end being the head. A pivotally mounted retraction lever disposed proximate to the pressure surface of the arm assembly; a mechanical biasing member for biasing the pressure end against the pressure surface; a trap for the retraction lever. A retractable lever lock arranged to trap and release the possible end; a voice coil motor that works efficiently with the head arm assembly; an upper guide surface and a lower guide surface, each guide surface being a ramp portion. And a flat portion having a knee between the flat portion and a flat unloading arm; . 14. A sleeve of energy absorbing material attached to the pressure end of the retracting lever,
14. The mechanical biasing member is a spring.
The described device. 15. The apparatus of claim 14 wherein a solenoid is swingably mounted on the retraction lever lock. 16. A disk drive system having a head arm assembly having a pressure surface, an upper flexure and a lower flexure respectively supporting the upper and lower read / write heads; a voice coil motor cooperating efficiently with the head arm assembly; Head unloading arm having a flat taper design with upper and lower guide surfaces along which the flexure slides, each guide surface including a knee between the flat and tapered portions; retractable lever lock A method of launching upper and lower read / write heads on a disk in a disk drive system, the method comprising: a retractable lever lock; a solenoid; and a biasing member: rotating the retractable lever and applying the retractable lever. A gap is formed between the pressure end and the pressure surface of the head arm assembly; the head arm assembly is directed toward the inner diameter of the disk until the pressure end of the retraction lever is close to the pressure surface of the head arm assembly. Controllably ramping the current of the voice coil motor to determine the speed of movement of the read / write head as the upper and lower flexures move away from the upper and lower guide surfaces of the head unload arm, respectively. Control; increase the current in the voice coil motor until the head arm assembly abuts the inward crashstop; trap the retractable end of the retract lever. 17. A voice coil motor current is oscillated to impair each frictional pressure between the upper and lower flexures and the upper and lower guide surfaces, whereby each of the flexures is The head arm assembly is rotated toward the inner diameter of the disk until it slides and slides through a knee of the guide surface located at the tapered portion of the flat taper ramp.
6. The method according to 6. 18. A disk drive system comprising a head arm assembly having a pressure surface; a head arm assembly placement motor; a retraction lever having wings, a pressure end and a trappable end; a retraction lever having a push pin and a first pin. Lock; a solenoid whose plunger is swingably attached to a pull-in lever lock; and a biasing member attached to the pull-in lever, which is a method of launching a read / write head onto a disk in a disk drive system. And: actuating a solenoid, which causes the push pin of the retraction lever lock to be pressed against the wing of the retraction lever to form a gap between the pressure end of the retraction lever and the pressure surface of the head arm assembly; Of the retracting lever Drive the head arm assembly toward the inner diameter of the disk until the pressure end is close to the pressure surface of the head arm assembly; the motor current until the pressure surface of the head arm assembly balances the force of the biasing member. The solenoid is deactivated; the motor current is increased until the head arm assembly abuts the inward crush pin; the solenoid is actuated, thereby trapping the trappable end of the retracting lever. 19. The method according to claim 18, wherein the step of driving the head arm assembly toward the inner diameter of the disk comprises oscillating the current of the voice coil motor. 20. A disk drive system for a head arm assembly having a pressure surface; a head arm assembly placement motor; a retracting lever having a pressure end and a trappable end; a retracting lever lock having a push pin; and a plunger thereof. Is composed of a solenoid swingably attached to the pull-in lever lock; a head unload arm; a biasing member attached to the pull-in lever. The disk drive encounters power loss while the disk is loaded into the drive. A method of using the stored mechanical energy to retract the read / write head of a disk drive when operating: using the head arm assembly placement motor to build potential energy in the mechanical biasing member. Store the potential energy in the mechanical biasing member; automatically release the stored potential energy when the disk drive encounters a power loss; apply the released energy to the retracting lever And pulling the head arm assembly onto the head unload arm; 21. The mechanical biasing member comprises a spring, and the step of using activates the head arm assembly placement motor to rotate the head arm assembly toward the center of the disk, thereby causing the head to move. 21. The method of claim 20 including the step of driving the pressure surface of the arm assembly toward the pressure end of the retraction lever, thereby rotating the retraction lever and pulling the spring. 22. The accumulating step activates the solenoid to rotate the retraction lever lock, thereby trapping the trappable end of the retraction lever of the retraction lever behind the trapping pin of the retraction lever lock. 22. The method of claim 21 including the step of: 23. The releasing step includes the step of relaxing the solenoid to rotate the retractable lever lock to release the trappable end of the retractable lever from behind the trap pin of the retractable lever lock. 23. The method of claim 22. 24. The method according to claim 23, wherein the method further comprises the step of controlling the retraction speed of the head to be substantially constant regardless of the start position of the head on the disk. 25. A disk drive system comprising a head arm assembly having a pressure surface; a head arm assembly placement motor; a retractable lever having a pressure end and a trappable end; a retractable lever lock; A method for retracting a read / write head in a disk drive, which comprises a solenoid swingably mounted on a revolving lever lock to rotate a retraction lever lock; a head unload arm; a biasing member mounted on the retraction lever. Extending the biasing member; actuating the solenoid to rotate the retracting lever lock in the first direction; the retracting lever lock captures the trappable end of the retracting lever and stores the retracting energy in the extended biasing member. Do; turn off the solenoid Rotate the retraction lever lock in a second direction, which releases the retraction lever to release the stored retraction energy; the released energy until the head arm assembly comes to rest on the head unload arm. Drive the pressure end of the retraction lever toward the pressure surface of the head arm assembly. 26. The method of claim 25, wherein the biasing member comprises a spring connected between the retracting spring hook and the retracting lever, and the step of extending the biasing member is the step of pulling the spring.