Disc drive with multiple actuators on pivot axis

Abstract

Disc drives with multiple actuators on a pivot axis are disclosed. A data storage device includes a stack of data storage discs mounted on a spindle, a first arm, and a second arm. The stack includes a first plurality of upper discs and a second plurality of lower discs. The first arm is movably attached to an actuator pivot, the first arm having a first head end portion that supports a first head, the first arm configured to move along a first portion of the actuator pivot to enable the first head to interact with data storage surfaces of the first plurality of upper discs. The second arm has a second head end portion that supports a second head, the second arm attached to a second portion of the actuator pivot and configured to move along the second portion of the actuator pivot independently of the first arm to enable the second head to interact with data storage surfaces of the second plurality of lower discs.

Description

Summary of the Invention

[0001] In one embodiment, a data storage device includes a stack of data storage disks mounted on a spindle, a first arm, and a second arm. The stack includes a first plurality of upper disks and a second plurality of lower disks. The first arm is movably attached to an actuator shaft, the first arm having a first head end supporting a first head, the first arm being configured to move along a first portion of the actuator shaft to enable the first head to interact with data storage surfaces of the first plurality of upper disks. A second arm is movably attached to the actuator shaft, the second arm having a second head end supporting a second head, the second arm being configured to move independently of the first arm along a second portion of the actuator shaft to enable the second head to interact with data storage surfaces of the second plurality of lower disks.

[0002] In another embodiment, a data storage device includes: a stack of multiple data storage disks, first and second actuator shafts, first and second arms, first and second heads, and first and second linear actuators. The stack includes a first read / write surface defining an xy plane and a second read / write surface parallel to the first read / write surface. The first and second actuator shafts are aligned end-to-end and have a common longitudinal axis. A first arm is movably attached to the first actuator shaft, the first arm having a first head end that is movable relative to the first read / write surface. The first head is supported by the first head end of the first arm, wherein the first head is configured to interact with the first read / write surface. The first linear actuator is configured to move the first arm along the first actuator shaft. A second arm is movably attached to the second actuator shaft, the second arm having a second head end that is movable relative to the second read / write surface. The second head is supported by the second head end of the second arm, wherein the second head is configured to interact with the second read / write surface. The second linear actuator is configured to move the second arm along the second actuator axis independently of movement of the first arm along the first actuator axis.

[0003] In yet another embodiment, a method includes moving a first arm and a second arm in a z-direction. The first arm is moved in the z-direction along a longitudinal axis to position a first head of the first arm relative to a first plurality of data storage disks. Independent of moving the first arm in the z-direction, the second arm is moved in the z-direction along the longitudinal axis to position a second head of the second arm relative to a second plurality of data storage disks.

[0004] Other features and advantages that characterize embodiments of the present disclosure will become apparent upon reading the following detailed description and reviewing the associated drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a schematic illustration of an exemplary data storage device.

[0006] Figure 2is a perspective view of portions of a dual-head stacking assembly for a data storage device.

[0007] Figure 3 is a perspective view of a portion of a head stack assembly showing a cage through which a pin of a lock may extend.

[0008] Figure 4 is a perspective view of an exemplary actuator arm including a receptacle configured to receive each locking pin.

[0009] Figure 5 is a partially transparent perspective view of an exemplary lock.

[0010] Figure 6 It is along Figure 5 6-6 of the lock in the default protruding, locked configuration.

[0011] Figure 7 is a cross-sectional view of the lock in the energized, retracted and unlocked configuration.

[0012] Figure 8 It is along Figure 5 A partial cross-sectional view of the assembly including the lock, HAS retainer and actuator arm in the locked configuration taken along line 8-8.

[0013] Figure 9 is a flow chart of an example method for using the described system. DETAILED DESCRIPTION

[0014] In general, embodiments of the present disclosure relate to hard disk drives (HDDs) having fewer heads than the number of disk surfaces. This greatly reduces the cost associated with conventionally large numbers of read / write heads and related systems. However, having a single head assembly per HDD can result in reduced performance due to the time it takes to move the head assembly between disks. Therefore, some systems use multiple actuator arms and head assemblies in each disk stack. Most commonly, the two arms are placed on different sides of the disk, taking up valuable space in drives of typical form factors.

[0015] In an embodiment of the present disclosure, multiple actuator arms and head assemblies are used to improve performance, but space savings are achieved by providing multiple arms and head assemblies on the same longitudinal pivot axis. In an exemplary embodiment, each of the two assemblies has an independently movable arm that moves up and down a pivot axis, as well as rotates on and off the disk stack. For example, in a 10-disk stack, one head stack assembly can read and write relative to the top five disks, while a second head stack assembly can read and write relative to the bottom five disks. An electromagnetic locking scheme is disclosed to independently prevent z-direction movement of each of the head stack assemblies. While a specific number of head stack assemblies is described for a specific number of disks in a stack, it is contemplated that more or fewer head stack assemblies can be used with more or fewer disks in the stack. It is primarily contemplated that more than one head stack assembly be provided for a single stack, and that the multiple head stack assemblies share a common pivot axis (such as defined by a single shared magnetic axis in the exemplary embodiment).

[0016] The present disclosure generally relates to data storage devices utilizing magnetic storage media, such as hard disks. The storage capacity of hard disk drives has steadily increased due to increases in areal density brought about by technological advancements such as perpendicular recording, shingled magnetic recording (SMR), heat-assisted magnetic recording (HAMR), interleaved magnetic recording (IMR), microwave-assisted magnetic recording (MAMR), and helium filling.

[0017] One way to address the demand for higher HDD performance is to utilize multiple read / write heads in parallel. This parallelism can increase the rate of input / output operations (IOPS), thereby speeding up certain operations. Using read / write heads operating simultaneously can provide other options; for example, an HDD can be configured with regions with different throughput levels and capacity levels, and multiple heads can be operated in different modes to increase throughput in some regions while increasing capacity (or other performance parameters) in other regions.

[0018] In the embodiments described below, a hard disk drive includes multiple heads driven by separate actuators that can read from and / or write to one or more disks simultaneously. Activating the heads simultaneously can be used to increase data rates or for other purposes (such as, for example, improving reliability or servicing different requests in parallel). The drive's signal processing circuitry may include parallel processing paths. For example, the processing circuitry may include multiple read / write channels for processing (e.g., decoding and / or encoding) user and control data. The processing circuitry may also include multiple servo control logic sections that allow data from each reader to be used to servo control one or more heads in which the reader is embedded. The servo logic also provides timing signals used by the signal processing logic.

[0019] Additional information related to high performance of disk drives is provided in the following commonly owned patent applications and patents, which are hereby incorporated by reference: U.S. Published Patent Application No. 2004 / 0257710, “Harddrive actuator arm with reduced skew variation”; U.S. Patent No. 6,356,404, “Simultaneously biasing multiple magneto-resistive read elements”; U.S. Patent No. 6,987,637, “Magnetic recording system which eliminates skew angle effect”; U.S. Patent No. 9,361,919, “Disk drive with parallel head actuation”; and U.S. Patent No. 10,818,317, “Multi-actuator data system”.

[0020] Typically, a head support ramp is provided near the outer diameter (OD) of one or more disks in a hard disk drive to prevent the read / write head from landing on one or more disks in the hard disk drive, for example, when the HDD is powered off, and to prevent the head from colliding with the outer edge of the disk during loading and unloading operations. In current HDDs, the number of heads is equal to the number of active disk surfaces, and the heads are rotated to be positioned above their corresponding disk surfaces. There is typically no up / down movement of the heads in such HDDs. However, for example, in "elevator" drives, the number of heads employed is less than the number of disk surfaces, and a head stack assembly (HSA) comprising a smaller number of heads moves up and down to enable a single head to read from multiple disk surfaces. Suitable elevator configurations include, for example, those described in the following commonly owned patent, which is hereby incorporated by reference: U.S. Patent No. 10,269,380, "Disk drive having multiple disks accessible by a reduced number of read / write heads."

[0021] This up / down movement is possible when the HAS is rotated so that the head is away from the disk and supported on the ramp. A conventional ramp is a single unit where the ramp edge is above the OD of the disk. This ramp design prevents the ramp from moving up / down with the HSA because the ramp edge above the OD may collide with the disk during the up / down movement of the ramp. Some embodiments of the present disclosure employ a split ramp that includes a first ramp portion adjacent to the OD of the disk and a vertically movable ramp portion adjacent to the first ramp portion. In order to enable the HAS to move up / down, the HSA is first rotated away from the disk and the first ramp (if any), and the HSA is positioned so that the head is supported on the movable ramp portion. The HSA and the movable portion of the ramp are then moved in unison by an elevator in the HDD. Although specific embodiments of a movable ramp are shown in the figures, it should be understood that other ramp configurations may also be used, such as those described in the following commonly owned patent applications, which are hereby incorporated by reference: U.S. application 16 / 863,287, filed on April 30, 2020, entitled “SplitRamp for Data Storage Devices”; and U.S. application 16 / 863,287, filed on February 1, 2021, entitled “Ramp Activation Systems for an ElevatorDrive”.

[0022] Figure 1 An illustrative operating environment is shown in which certain embodiments disclosed herein may be incorporated. Figure 1 The operating environment shown is for illustration purposes only. The embodiments of the present disclosure are not limited to any particular operating environment, such as Figure 1 Operating Environment Depicted. Embodiments of the present disclosure may be illustratively practiced within any number of different types of operating environments.

[0023] It should be noted that, for identical or similar elements, the same reference numerals are used in different drawings. Unless otherwise indicated, all descriptions of elements are also applicable to all other versions of the element. It should be understood that the terms used herein are only for the purpose of describing the embodiments, and the terms are not intended to be limiting. Unless otherwise indicated, ordinal numbers (e.g., first, second, third, etc.) are used to distinguish or identify the different elements or steps in a group of elements or steps, and do not provide sequence or numerical value restrictions for the elements or steps of their embodiments. For example, "first," "second," and "third" elements or steps do not necessarily appear in this order, and their embodiments are not necessarily limited to three elements or steps. It should also be understood that, unless otherwise indicated, any labels, such as "left," "right," "front," "back," "top," "bottom," "forward," "opposite," "clockwise," "counterclockwise," "up," "down," or other similar terms, such as "above," "below," "tail," "front," "vertical," "horizontal," "proximal," "distal," "middle," etc., are used for convenience and are not intended to represent, for example, any specific fixed position, orientation, or direction. On the contrary, such labels are used to reflect, for example, relative position, orientation, or direction. It is also to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0024] It should be understood that when an element is referred to as being "connected," "coupled," or "attached" to another element, the element may be directly connected, coupled, or attached to the other element, or the element may be indirectly connected, coupled, or attached to the other element with intervening or intermediate elements present. In contrast, if an element is referred to as being "directly connected," "directly coupled," or "directly attached" to another element, there are no intervening elements present. The accompanying drawings illustrate direct connections, couplings, or attachments between elements and also include embodiments in which elements are indirectly connected, coupled, or attached to each other.

[0025] Figure 1 1 is a schematic diagram of a data storage device (DSD) 100, which includes a data storage medium, a head for reading data from the data storage medium and / or writing data to the data storage medium, and a split ramp for supporting the head. In the data storage device 100, the head 102 can be positioned above the storage medium 104 to read data from the data storage medium 104 and / or write data to the data storage medium 104. Figure 1In the embodiment shown, the data storage medium 104 is a stack of rotatable data storage disks on a spindle 105, wherein each disk 104 has opposing surfaces that serve as data storage surfaces. For read and write operations, a spindle motor 106 (shown schematically) rotates the medium 104 as indicated by arrow 107, and a dual actuator mechanism 110 positions the head 102 between an inner diameter (ID) 108 and an outer diameter (OD) 109 relative to a data track 114 on the rotating medium 104. Both the spindle motor 106 and the actuator mechanism 110 are connected to and operated by a driver circuit system 112 (shown schematically). In the embodiment shown, the head 102 is connected to the top head stack assembly 138. T Some reference numerals associated with elements of the bottom header stacking assembly 138 include a subscript "T" designation and are B Reference numerals associated with elements include a suffix "B" designation.

[0026] Each of the heads 102 is coupled to its corresponding actuator mechanism 110 via a suspension assembly that includes a load beam 120 connected to an actuator arm 122 of the mechanism 110, for example, by a swaged connection. The actuator mechanism 110 is rotationally coupled to a frame or base plate 144 via a pivot shaft 124 for rotation about a longitudinal axis 126 of the pivot shaft 124. The actuator mechanism 110 moves the head 102 in a cross-track direction as indicated by arrow 130. Each of the heads 102 includes one or more transducer elements (not shown) coupled to head circuitry 132 via a flex circuit 134.

[0027] Generally, in order to keep the read / write heads 102 from landing on the disks 104 in the data storage device 100 when the data storage device 100 is powered off, for example, and to prevent the heads 102 from colliding with the outer edges of the disks 104 during loading and unloading operations, a head support ramp assembly 136 is provided near the OD 109 of the disks 104. In the data storage device 100, the number of heads 102 is less than the number of disk 104 surfaces. Figure 1 In the particular embodiment shown, the data storage device 100 includes eight disks 104A, 104B, 104C, 104D, 104E, 104F, 104G, 104H having a total of 16 data storage surfaces, and two heads 102 on each of two actuator arms 122. Thus, a single data storage device 100 includes dual actuator mechanisms 110, dual actuator arms 122, and dual load beams 120. Top actuator mechanism 110 T , top actuator arm 122 T and the top load beam 120 are collectively referred to as the top head stack assembly (HSA) 138 T Bottom actuator mechanism 110 B, bottom actuator arm 122 B and bottom load beam ( Figure 1 Not visible in the figure) are collectively referred to as bottom header stacking assembly (HSA) 138 B .

[0028] exist Figure 1 In the data storage device 100, each actuator arm 122 can be moved to a different position along the axis 126 of the shaft 124 independently of the other actuator arms 122 under the drive of the corresponding elevator 140, as shown in the schematic diagram. Figure 1 In the uppermost position shown, coupled to the top actuator arm 122 T The two heads 102 interact with the upper and lower data storage surfaces of the disk 104A and are coupled to the bottom actuator arm 122. B The two heads 102 interact with the upper and lower data storage surfaces of the disk 104E.

[0029] In an exemplary embodiment, the two actuators 110 are independent. T Control top actuator arm 122 T Rotates about the axis 126 of the pivot shaft 124. Actuator 110 B Independently control the bottom actuator arm 122 B The top and bottom actuator arms 122 are each also movable by their own independent elevator 140. T or 140 B In the vertical z direction, the elevator 140 T Allows the top actuator arm 122 T In an exemplary embodiment, the elevator 140 has a limited vertical motion range to access the disk surfaces of the top four disks 104A, 104B, 104C, and 104D. T Also operatively connected to the movable ramp 136b T , with the top actuator arm 122 T In an exemplary embodiment, the elevator 140 B Allows the bottom actuator arm 122 B In an exemplary embodiment, the elevator 140 has a limited vertical motion range to access the disk surfaces of the bottom four disks 104E, 104F, 104G, and 104H. B Also operatively connected to the movable ramp 136b B , with the bottom actuator arm 122 B Move in unison in the z direction.

[0030] While the system is shown with eight disks 104 and two head stack assemblies 138, it is contemplated that the teachings described herein may be applied to disk stacks including any number of disks on a single spindle 105 and any number of head stack assemblies 138 arranged on a single rotational shaft 124 (or multiple linearly aligned shaft segments). At other locations (below the uppermost illustrated location) of the top and bottom actuator arms 122 (not shown), the same two actuator arm assemblies interact with the data storage surfaces of disks 104B, 104C, 104D, 104F, 104G, and 104H.

[0031] To make each HSA 138 T , 138 B Able to move up / down, in some embodiments, the head support ramp 136 is designed as a split ramp having a stationary portion 136a and a movable portion 136b. Each HSA 138 T , 138 B The actuator arm 122 can be moved from an upper position to a lower position or from a lower position to an upper position for its corresponding disk stack portion along the rotation axis 124 within a limited range. In either case, the actuator arm 122 is first rotated about the axis 126 until the head end 142 of the actuator arm 122 is supported on the corresponding movable portion 136b of the head support ramp assembly 136. T 、136b B Then, the paired actuator arms 122 and movable portion 136b are moved in unison along axis 126 (such as vertically or in the z-direction) by an operatively connected elevator 140. In some embodiments, the entire ramp 136 or a portion of the ramp 136 can also be moved out of the disk stack in the xy plane, such as by contracting, bending, or rotating.

[0032] In one embodiment, the elevator 140 T , 140 B It can be made of a coil and a hard stop at both ends (such as Figure 2 and Figure 3 The elevator 140 is driven up and down by magnets (not shown) of a plate 150 (shown), with hard stops limiting the upward and downward range of motion of the corresponding HSA 138. In general, any suitable drive mechanism can be used to move the elevator 140 up and down. Exemplary drives for Z-direction motion of the elevator 140 include ball screws with internal motors, voice coil motors, inchworm brake tracks, linear motors, shape memory alloy-based actuators, and combinations thereof.

[0033] like Figure 2As indicated in FIG, in some embodiments, each actuator arm 122 includes an upper plate 122a and a lower plate 122b separated by a channel 148 sized to allow the plates 122a, 122b to fit above and below the disk 104 without physically contacting the disk 104. Attached to the ends of the upper and lower plates 122a, 122b are respective upper and lower load beam portions ( Figure 2 1 (not shown) carries heads 102 for reading and writing on the top and bottom surfaces of disks 104. Lifting tabs extend from load beam 120 to rest on head support ramp assembly 136 when disk drive storage device 100 is in a closed or non-operating state.

[0034] To read and write data relative to disk 104 using head 102 , selected actuators 110 are activated to rotate actuator arm 122 about pivot shaft 124 , pivot bearing 160 , and pivot axis 126 , thereby moving head end 142 of HSA 138 out of head support ramp assembly 136 and toward disk 104 .

[0035] like Figure 2 As shown, each arm 122 has an associated elevator in the form of a linear axis motor 128 that allows the respective arm 122 to move vertically between plates 150; the plates 150 act as hard stops for the motion. In the exemplary embodiment, the linear axis motor 128 T and 128 B (and their respective actuator arms 122) both travel along a single longitudinal axis 126. The pivot axis 124 may be provided as a single, unitary elongated member. Alternatively, the head stack assembly 138 T and 138 B Each of the linear servomotors 128 may have its own shaft 124, in which case the separate shafts will be aligned end-to-end along the same axis 126. Suitable linear shaft motors 128 are commercially available from Nippon Pulse, Inc. of Radford, Virginia, as linear servomotors. Suitable linear servomotors include a shaft made of a rare earth-iron-boron permanent neodymium magnet and a "forcer" comprising a cylindrically wound coil that may be equipped with an optional Hall effect device. The magnetic shaft 124 provides the magnetic field that the forcer of the motor 128 acts upon.

[0036] Figure 3 is a perspective view of a portion of the head stack assembly 138 showing a holder 152 extending between baffles 150 and having holes 154 (in Figure 8), the pin 156 of the lock 158 can extend through the hole 154. In the exemplary embodiment, each of the plates 150 fixes a pivot bearing 160, and the magnetic shaft 124 extends through the pivot bearing 160. Figure 4-Figure 8 As shown, in the exemplary embodiment, the arm 122 includes a receptacle 162 configured to receive each locking key or pin 156 . Figure 5 is a partially transparent view of an exemplary lock 158 . Figure 6 It is along Figure 5 6-6 of FIG. 1 , showing a cross-sectional view of the lock 158 in the default protruding, locked configuration. Figure 7 is a cross-sectional view of the lock 158 in an energized, retracted and unlocked configuration. Figure 8 It is along Figure 5 8, which includes a lock 158 in a locked configuration with a HSA cage 152 and an actuator arm 122. Each of the HSAs 138 operates individually and simultaneously to perform read, write, seek, and lift tasks, allowing the hard drive to achieve approximately twice the performance of a drive having only a single actuator and arm assembly.

[0037] In the illustrated embodiment, twelve locks 158 are shown extending through the retaining frame 152 so that the pins 156 can be inserted into the receptacles 162 of the actuator arms 122. However, it is contemplated that more or fewer locking devices of varying sizes may be used. In the illustrated configuration, the twelve locks 158 are arranged in four horizontal rows, each row corresponding to a vertical position of the actuator arms 122 to position the upper arm 122a and lower arm 122b above and below one of the four trays in the tray stack portion for the associated HSA 138. Thus, the vertical positioning of the actuator arms 122 is locked in one of four discrete vertical positions, thereby providing accurate vertical placement of the actuator arms 122. In the default configuration, each actuator arm 122 is locked in one of the four vertical positions. When vertical movement of the actuator arm 122 is desired, the lock 158 is energized to retract the pin 156 from the receptacle 162 so that the actuator arm 122 can move under the power of the linear axis motor 128 , which is a specific form of elevator 140 .

[0038] Figure 6 Shown along Figure 5 A cross-sectional view of an exemplary lock 158 is shown taken along line 6-6 of FIG. In the exemplary embodiment, the lock 158 includes an electromagnetic coil 164 surrounding an iron bolt 166. Figure 6In the default configuration shown, when the solenoid 164 is not energized, a gap 168 is maintained between the bolt 166 and the iron key 170. A coil spring 172 surrounds a portion of the shaft 174 of the key 170, the spring being trapped between a shoulder 176 of the key body 180 and a flange 178 of the key 170.

[0039] like Figure 7 As shown, to retract the pin 156 into the body 180 of the lock 158, the solenoid 164 is energized, causing the iron bolt 166 to act as a magnet and attract the iron shaft 174 of the key 170. Consequently, the gap 168 closes, and the spring 172 is compressed between the flange 178 of the key 170 and the shoulder 176 of the lock body 180. The axial movement of the key 170 within the body 180 of the lock 158 retracts the pin 156 sufficiently to remove it from the receptacle 162 of the actuator arm 122. While a portion of the pin 156 still extends outside the body 180, the size of this portion is substantially the same as the thickness of the retainer 152 at the aperture 154, thereby unlocking the actuator arm 122 from the retainer 152. In the exemplary embodiment, the head circuitry 132 for each of the actuators 110 coordinates control of all twelve locks 158 for the retainer 152. Thus, all of the locks 158 for a particular cage 152 are energized (unlocked) or de-energized (locked) in unison. With the lock 158 energized, the pin 156 is thereby pulled out of the corresponding socket 162, freeing the associated actuator arm 122 to move up and down in the z-direction along the steel shaft 124 under the drive of the linear shaft motor 128. When the actuator arm 122 reaches the appropriate position on the shaft 124, the solenoid 164 of each of the locks 158 of the actuator assembly 110 is thereby de-energized, and the spring returns to its uncompressed configuration, thereby biasing the actuator arm 122 to the desired position. Figure 6 The default locked position is shown to maintain the actuator arm 122 in a selected vertical position on the shaft 124.

[0040] Figure 9 is a flow chart of an exemplary method 200 for using the data storage device 100, which begins at 201. The bottom HSA 138 follows the sequence of steps 232-242. B Compared to the top HAS138 T A completely independent sequence of steps 202-212 is followed. At 202, for the top HSA 138 T , the electromagnetic (EM) coil 164 is energized to unlock the top actuator arm 122 T At 204, the linear pivot motor 128 T is activated to move the top actuator arm 122 TThe EM coil 164 is de-energized at 206 to move the top actuator arm 122 to the desired position in the z direction to access a particular disk 104 in the upper stack of disks. T Locked to the desired vertical position. At 208, the top actuator arm 122 T The head 102 is rotated on the spindle 124 about the axis 126 to position its head end 142 in a read / write position relative to the desired data track 114. At 210, the head 102 on the head end 142 performs a read / write operation on the track 114. At 212, the top actuator arm 122 T The top HSA 138 rotates on the shaft 124 about the axis 126 to return its head end 142 to rest on the ramp 136. T To perform more read / write operations, the method returns to 202. If the arm is already at the appropriate Z position, the method jumps to 208.

[0041] Bottom HSA 138 B With top HSA 138 T Simultaneously but independently of the top HSA 138 T Operation, follow the sequence of steps 232-242. At 232, for the bottom HSA 138 B , the EM coil 164 is energized to unlock the bottom actuator arm 122 B At 234, the linear pivot motor 128 B is activated to move the bottom actuator arm 122 B Move to the desired position in the z direction to access a specific disk 104 in the lower stack of disks. At 236, the EM coil 164 is de-energized to move the bottom actuator arm 122 B Locked to the desired vertical position. At 238, the bottom actuator arm 122 B The head 102 is rotated on the spindle 124 about the axis 126 to position its head end 142 in a read / write position relative to the desired data track 114. At 240, the head 102 on the head end 142 performs a read / write operation on the track 114. At 242, the bottom actuator arm 122 B The HSA 138 rotates on the shaft 124 about the axis 126 to return its head end 142 to rest on the ramp 136. B To perform more read / write operations, the method returns to 232. If the arm is already at the appropriate Z position, the method jumps to 238.

[0042] The illustrations of the embodiments described herein are intended to provide a general understanding of the structures of the various embodiments. The illustrations are not intended to serve as a complete description of all elements and features of the devices and systems that utilize the structures or methods described herein. Features described with respect to any embodiment also apply to any other embodiment. Upon reviewing this disclosure, many other embodiments may be apparent to those skilled in the art. Other embodiments may be utilized and derived from this disclosure, so that structural and logical replacements and changes may be made without departing from the scope of this disclosure. Additionally, the illustrations are representative only and may be drawn to scale. Certain proportions in the illustrations may be exaggerated, while other proportions may be reduced. Therefore, this specification and the drawings should be regarded as illustrative rather than restrictive.

[0043] One or more embodiments of the present invention may be referred to herein individually and / or collectively by the term "invention", for convenience only, and are not intended to limit the scope of this application to any particular invention or inventive concept. In addition, although specific embodiments have been shown and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may replace the specific embodiments shown. This disclosure is intended to cover any and all subsequent modifications or variations of the various embodiments. For those skilled in the art, after reviewing the above description, the combination of the above-described embodiments and other embodiments not specifically described herein will be apparent. All patent documents mentioned in this specification are incorporated herein by reference.

[0044] The Abstract of the present disclosure is provided to comply with 37 CFR §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing detailed description, various features may be grouped together or described in a single embodiment for the purpose of cohesively integrating the disclosure. This disclosure should not be interpreted to reflect an intention that the claimed embodiments employ more features than expressly recited in the various claims. On the contrary, as reflected in the following claims, the subject matter of the present disclosure may involve fewer than all of the features of any of the disclosed embodiments.

[0045] The subject matter disclosed above is intended to be considered illustrative rather than restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the true spirit and scope of the disclosure. For example, features described with respect to one embodiment may be incorporated into other embodiments. Therefore, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest interpretation permitted by the appended claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

[0046] Further examples:

[0047] Example 1. A data storage device comprising: a stack of data storage disks mounted on a spindle, the stack comprising a first plurality of upper disks and a second plurality of lower disks; a first arm, the first arm movably attached to an actuator shaft, the first arm having a first head end supporting a first head, the first arm being configured to move along a first portion of the actuator shaft to enable the first head to interact with data storage surfaces of the first plurality of upper disks; and a second arm, the second arm movably attached to the actuator shaft, the second arm having a second head end supporting a second head, the second arm being configured to move along a second portion of the actuator shaft independently of the first arm to enable the second head to interact with data storage surfaces of the second plurality of lower disks.

[0048] Example 2. The data storage device of Example 1, wherein each of the first portion of the actuator shaft and the second portion of the actuator shaft is parallel to the main axis.

[0049] Example 3. The data storage device of Example 1, comprising a first linear axis motor configured to move the first arm along the first portion of the actuator axis.

[0050] Example 4. The data storage device of Example 3, comprising a second linear axis motor configured to move the second arm along the second portion of the actuator axis.

[0051] Example 5. The data storage device of Example 1, comprising a pivot bearing between the first arm and the first portion of the actuator shaft.

[0052] Example 6. The data storage device of Example 1, comprising two plates disposed at opposite ends of the first portion of the actuator shaft.

[0053] Example 7. The data storage device of Example 1, wherein the first arm includes a receptacle on a second end of the first arm opposite the first head end.

[0054] Example 8. The data storage device of Example 7, comprising: a retaining frame connected to the first portion of the actuator shaft; and a lock comprising a pin configured to extend through a hole in the retaining frame and into the receptacle.

[0055] Example 9. The data storage device of Example 8, wherein the lock comprises a solenoid configured to retract the pin from the receptacle.

[0056] Example 10. The data storage device of Example 8, comprising a coil spring configured to bias the pin into the receptacle.

[0057] Example 11. The data storage device of Example 8, wherein the lock is one of a plurality of locks spaced apart along the retaining frame at locations corresponding to the first plurality of upper disks.

[0058] Example 12. The data storage device of Example 1, comprising a movable ramp configured to move in unison with the first arm in a z-direction parallel to the first portion of the actuator axis of rotation.

[0059] Example 13. A data storage device comprising: a stack of a plurality of data storage disks, the stack comprising a first read / write surface defining an xy plane and a second read / write surface parallel to the first read / write surface; a first actuator shaft and a second actuator shaft, the first actuator shaft and the second actuator shaft being aligned end to end and having a common longitudinal axis; a first arm movably attached to the first actuator shaft, the first arm having a first head end portion movable relative to the first read / write surface; a first head supported by the first head end portion of the first arm, wherein the first head is configured to engage with the first head end portion of the first arm. a first linear actuator configured to move the first arm along the first actuator axis; a second arm movably attached to the second actuator axis, the second arm having a second head end movable relative to the second read / write surface; a second head supported by the second head end of the second arm, wherein the second head is configured to interact with the second read / write surface; and a second linear actuator configured to move the second arm along the second actuator axis independently of movement of the first arm along the first actuator axis.

[0060] Example 14. The data storage device of Example 13, comprising a first rotary actuator configured to pivot the first arm about the first actuator axis.

[0061] Example 15. The data storage device of Example 14, comprising a second rotary actuator configured to pivot the second arm about the second actuator axis independently of movement of the first arm about the first actuator axis.

[0062] Example 16. The data storage device of Example 13, wherein the first arm includes a receptacle on a second end of the first arm opposite the head end.

[0063] Example 17. The data storage device of Example 16, comprising: a retaining frame connected to the first actuator shaft; and a lock comprising a pin configured to extend through a hole in the retaining frame and into the receptacle.

[0064] Example 18. A method comprising: moving a first arm in a z direction along a longitudinal axis to position a first head of the first arm relative to a first plurality of data storage disks; and independently of moving the first arm in the z direction, moving a second arm in the z direction along the longitudinal axis to position a second head of the second arm relative to a second plurality of data storage disks.

[0065] Example 19. The method of Example 18, comprising: rotating the first arm about the longitudinal axis to position the first head relative to one of the first plurality of data storage disks; and rotating the second arm about the longitudinal axis independently of rotating the first arm to position the second head relative to one of the second plurality of data storage disks.

[0066] Example 20. The method of Example 18, comprising locking the first arm in the z-direction along the longitudinal axis.

Claims

1. A data storage device comprising: a stack of data storage disks mounted on a spindle, the stack comprising a first plurality of upper disks and a second plurality of lower disks; a first arm movably attached to an actuator shaft, the first arm having a first head end supporting a first head, the first arm being configured to move along a first portion of the actuator shaft to enable the first head to interact with data storage surfaces of the first plurality of upper disks; as well as a second arm movably attached to the actuator shaft, the second arm having a second head end supporting a second head, the second arm being configured to move independently of the first arm along a second portion of the actuator shaft to enable the second head to interact with the data storage surfaces of the second plurality of lower disks.

2. The data storage device according to claim 1, wherein Each of the first portion of the actuator shaft and the second portion of the actuator shaft is parallel to the main axis.

3. The data storage device of claim 1, comprising a first linear shaft motor configured to move the first arm along the first portion of the actuator shaft.

4. The data storage device of claim 3, comprising a second linear shaft motor configured to move the second arm along the second portion of the actuator shaft.

5. The data storage device of claim 1, comprising a pivot bearing between the first arm and the first portion of the actuator shaft.

6. The data storage device of claim 1, comprising two plates disposed at opposite ends of the first portion of the actuator shaft.

7. The data storage device according to claim 1, wherein The first arm includes a receptacle on a second end of the first arm opposite the first head end.

8. The data storage device of claim 7, comprising: a retainer coupled to the first portion of the actuator shaft; as well as A lock includes a pin configured to extend through the aperture of the retainer and into the receptacle.

9. The data storage device according to claim 8, wherein The lock includes a solenoid configured to retract the pin from the receptacle.

10. The data storage device of claim 8, comprising a coil spring configured to bias the pin into the receptacle.

11. The data storage device according to claim 8, wherein The lock is one of a plurality of locks spaced along the retainer at locations corresponding to the first plurality of upper discs.

12. The data storage device of claim 1, comprising a movable ramp configured to move in unison with the first arm in a z-direction parallel to the first portion of the actuator axis of rotation.

13. A data storage device comprising: a stack of a plurality of data storage disks, the stack comprising a first read / write surface defining an xy plane and a second read / write surface parallel to the first read / write surface; a first actuator shaft and a second actuator shaft, the first actuator shaft and the second actuator shaft being aligned end to end and having a common longitudinal axis; a first arm movably attached to the first actuator shaft, the first arm having a first tip portion movable relative to the first read / write surface; a first head supported by the first head end of the first arm, wherein the first head is configured to interact with the first read / write surface; a first linear actuator configured to move the first arm along the first actuator axis; a second arm movably attached to the second actuator shaft, the second arm having a second head end portion movable relative to the second read / write surface; a second head supported by the second head end of the second arm, wherein the second head is configured to interact with the second read / write surface; as well as A second linear actuator is configured to move the second arm along the second actuator axis independently of movement of the first arm along the first actuator axis.

14. The data storage device of claim 13, comprising a first rotary actuator configured to pivot the first arm about the first actuator axis.

15. The data storage device of claim 14, comprising a second rotary actuator configured to pivot the second arm about the second actuator axis independently of movement of the first arm about the first actuator axis.

16. The data storage device according to claim 13, wherein The first arm includes a receptacle on a second end of the first arm opposite the head end.

17. The data storage device of claim 16, comprising: a retainer connected to the first actuator shaft; as well as A lock includes a pin configured to extend through the aperture of the retainer and into the receptacle.

18. A method for data storage, comprising: moving the first arm in a z-direction along the longitudinal axis to position a first head of the first arm relative to a first plurality of data storage disks; as well as Independent of moving the first arm in the z-direction, the second arm is moved along the longitudinal axis in the z-direction to position a second head of the second arm relative to a second plurality of data storage disks.

19. The method of claim 18, comprising: rotating the first arm about the longitudinal axis to position the first head relative to one of the first plurality of data storage disks; as well as Independent of rotating the first arm, the second arm is rotated about the longitudinal axis to position the second head relative to one of the second plurality of data storage disks.

20. The method of claim 18, comprising locking the first arm in the z-direction along the longitudinal axis.

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