Patent Description:
There is an increasing need for archival storage. Tape is a traditional solution for data back-up, but is very slow to access data. Current archives are increasingly "active" archives, meaning some level of continuing random read data access is required. Traditional hard disk drives (HDDs) can be used but cost may be considered undesirably high. Other approaches considered may include HDDs with extra large diameter disks and HDDs having an extra tall form factor, with both requiring large capital investment due to unique components and assembly processes, low value proposition in the context of cost savings, and barriers to adoption in the marketplace due to uniquely large form factors, for example. <CIT> refers to a disk drive having multiple disks accessible by a reduced number of read/write heads. <CIT> discloses a position sensor.

Any approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. The invention is defined in the independent claim.

The dependent claims describe preferred embodiments of the invention.

Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:.

Approaches to a multi-disk hard disk drive having an actuator elevator mechanism and a ramp elevator mechanism are described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention described herein. It will be apparent, however, that the embodiments of the invention described herein may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the embodiments of the invention described herein.

Embodiments may be used in the context of a multi-disk, reduced read-write head, digital data storage device (DSD) such as a hard disk drive (HDD). Thus, in accordance with an embodiment, a plan view illustrating a conventional HDD <NUM> is shown in <FIG> to aid in describing how a conventional HDD typically operates.

<FIG> illustrates the functional arrangement of components of the HDD <NUM> including a slider 110b that includes a magnetic read-write head 110a. Collectively, slider 110b and head 110a may be referred to as a head slider. The HDD <NUM> includes at least one head gimbal assembly (HGA) <NUM> including the head slider, a lead suspension 110c attached to the head slider typically via a flexure, and a load beam 110d attached to the lead suspension 110c. The HDD <NUM> also includes at least one recording medium <NUM> rotatably mounted on a spindle <NUM> and a drive motor (not visible) attached to the spindle <NUM> for rotating the medium <NUM>. The read-write head 110a, which may also be referred to as a transducer, includes a write element and a read element for respectively writing and reading information stored on the medium <NUM> of the HDD <NUM>. The medium <NUM> or a plurality of disk media may be affixed to the spindle <NUM> with a disk clamp <NUM>.

The HDD <NUM> further includes an arm <NUM> attached to the HGA <NUM>, a carriage <NUM>, a voice-coil motor (VCM) that includes an armature <NUM> including a voice coil <NUM> attached to the carriage <NUM> and a stator <NUM> including a voice-coil magnet (not visible). The armature <NUM> of the VCM is attached to the carriage <NUM> and is configured to move the arm <NUM> and the HGA <NUM> to access portions of the medium <NUM>, all collectively mounted on a pivot shaft <NUM> with an interposed pivot bearing assembly <NUM>. In the case of an HDD having multiple disks, the carriage <NUM> may be referred to as an "E-block," or comb, because the carriage is arranged to carry a ganged array of arms that gives it the appearance of a comb.

An assembly comprising a head gimbal assembly (e.g., HGA <NUM>) including a flexure to which the head slider is coupled, an actuator arm (e.g., arm <NUM>) and/or load beam to which the flexure is coupled, and an actuator (e.g., the VCM) to which the actuator arm is coupled, may be collectively referred to as a head stack assembly (HSA). An HSA may, however, include more or fewer components than those described. For example, an HSA may refer to an assembly that further includes electrical interconnection components. Generally, an HSA is the assembly configured to move the head slider to access portions of the medium <NUM> for read and write operations.

With further reference to <FIG>, electrical signals (e.g., current to the voice coil <NUM> of the VCM) comprising a write signal to and a read signal from the head 110a, are transmitted by a flexible cable assembly (FCA) <NUM> (or "flex cable"). Interconnection between the flex cable <NUM> and the head 110a may include an arm-electronics (AE) module <NUM>, which may have an on-board pre-amplifier for the read signal, as well as other read-channel and write-channel electronic components. The AE module <NUM> may be attached to the carriage <NUM> as shown. The flex cable <NUM> may be coupled to an electrical-connector block <NUM>, which provides electrical communication, in some configurations, through an electrical feed-through provided by an HDD housing <NUM>. The HDD housing <NUM> (or "enclosure base" or "baseplate" or simply "base"), in conjunction with an HDD cover, provides a semi-sealed (or hermetically sealed, in some configurations) protective enclosure for the information storage components of the HDD <NUM>.

Other electronic components, including a disk controller and servo electronics including a digital-signal processor (DSP), provide electrical signals to the drive motor, the voice coil <NUM> of the VCM and the head 110a of the HGA <NUM>. The electrical signal provided to the drive motor enables the drive motor to spin providing a torque to the spindle <NUM> which is in turn transmitted to the medium <NUM> that is affixed to the spindle <NUM>. As a result, the medium <NUM> spins in a direction <NUM>. The spinning medium <NUM> creates a cushion of air that acts as an air-bearing on which the air-bearing surface (ABS) of the slider 110b rides so that the slider 110b flies above the surface of the medium <NUM> without making contact with a thin magnetic-recording layer in which information is recorded. Similarly in an HDD in which a lighter-than-air gas is utilized, such as helium for a non-limiting example, the spinning medium <NUM> creates a cushion of gas that acts as a gas or fluid bearing on which the slider 110b rides.

The electrical signal provided to the voice coil <NUM> of the VCM enables the head 110a of the HGA <NUM> to access a track <NUM> on which information is recorded. Thus, the armature <NUM> of the VCM swings through an arc <NUM>, which enables the head 110a of the HGA <NUM> to access various tracks on the medium <NUM>. Information is stored on the medium <NUM> in a plurality of radially nested tracks arranged in sectors on the medium <NUM>, such as sector <NUM>. Correspondingly, each track is composed of a plurality of sectored track portions (or "track sector") such as sectored track portion <NUM>. Each sectored track portion <NUM> may include recorded information, and a header containing error correction code information and a servo-burst-signal pattern, such as an ABCD-servo-burst-signal pattern, which is information that identifies the track <NUM>. In accessing the track <NUM>, the read element of the head 110a of the HGA <NUM> reads the servo-burst-signal pattern, which provides a position-error-signal (PES) to the servo electronics, which controls the electrical signal provided to the voice coil <NUM> of the VCM, thereby enabling the head 110a to follow the track <NUM>. Upon finding the track <NUM> and identifying a particular sectored track portion <NUM>, the head 110a either reads information from the track <NUM> or writes information to the track <NUM> depending on instructions received by the disk controller from an external agent, for example, a microprocessor of a computer system.

An HDD's electronic architecture comprises numerous electronic components for performing their respective functions for operation of an HDD, such as a hard disk controller ("HDC"), an interface controller, an arm electronics module, a data channel, a motor driver, a servo processor, buffer memory, etc. Two or more of such components may be combined on a single integrated circuit board referred to as a "system on a chip" ("SOC"). Several, if not all, of such electronic components are typically arranged on a printed circuit board that is coupled to the bottom side of an HDD, such as to HDD housing <NUM>.

References herein to a hard disk drive, such as HDD <NUM> illustrated and described in reference to <FIG>, may encompass an information storage device that is at times referred to as a "hybrid drive". A hybrid drive refers generally to a storage device having functionality of both a traditional HDD (see, e.g., HDD <NUM>) combined with solid-state storage device (SSD) using non-volatile memory, such as flash or other solid-state (e.g., integrated circuits) memory, which is electrically erasable and programmable. As operation, management and control of the different types of storage media typically differ, the solid-state portion of a hybrid drive may include its own corresponding controller functionality, which may be integrated into a single controller along with the HDD functionality. A hybrid drive may be architected and configured to operate and to utilize the solid-state portion in a number of ways, such as, for non-limiting examples, by using the solid-state memory as cache memory, for storing frequently-accessed data, for storing I/O intensive data, and the like. Further, a hybrid drive may be architected and configured essentially as two storage devices in a single enclosure, i.e., a traditional HDD and an SSD, with either one or multiple interfaces for host connection.

References herein to "an embodiment", "one embodiment", and the like, are intended to mean that the particular feature, structure, or characteristic being described is included in at least one embodiment of the invention. However, instance of such phrases do not necessarily all refer to the same embodiment,.

The term "substantially" will be understood to describe a feature that is largely or nearly structured, configured, dimensioned, etc., but with which manufacturing tolerances and the like may in practice result in a situation in which the structure, configuration, dimension, etc. is not always or necessarily precisely as stated. For example, describing a structure as "substantially vertical" would assign that term its plain meaning, such that the sidewall is vertical for all practical purposes but may not be precisely at <NUM> degrees.

While terms such as "optimal", "optimize", "minimal", "minimize", and the like may not have certain values associated therewith, if such terms are used herein the intent is that one of ordinary skill in the art would understand such terms to include affecting a value, parameter, metric, and the like in a beneficial direction consistent with the totality of this disclosure. For example, describing a value of something as "minimal" does not require that the value actually be equal to some theoretical minimum (e.g., zero), but should be understood in a practical sense in that a corresponding goal would be to move the value in a beneficial direction toward a theoretical minimum.

Recall that there is an increasing need for cost effective "active" archival storage (also referred to as "cold storage"), preferably having a conventional form factor and utilizing many standard components. One approach involves a standard HDD form factor (e.g., a <NUM>" form factor) and largely common HDD architecture, with n disks in one rotating disk stack, but containing fewer than 2n read-write heads, according to embodiments. Such a storage device may utilize an articulation mechanism that can move the heads to mate with the different disk surfaces (for a non-limiting example, only <NUM> heads but <NUM>+ disks for an air drive or <NUM>+ disks for a He drive), where the primary cost savings may come from eliminating the vast majority of the heads in the drive.

Ramp load/unload (LUL) technology involves a mechanism that moves the head stack assembly (HSA), including the read-write head sliders, away from and off the disks and safely positions them onto a cam-like structure. The cam typically includes a shallow ramp on the side closest to the disk. During a power-on sequence, for example, the read-write heads are loaded by moving the sliders off the ramp and over the disk surfaces when the disks reach the appropriate rotational speed. Thus, the terminology used is that the sliders or HSA are "loaded" to or over the disk (i.e., off the ramp) into an operational position, and "unloaded" from the disk (i.e., onto the ramp) such as in an idle position. In the context of a multi-disk HDD having an actuator elevator mechanism, in order to move the heads up and down to different disks the heads need to be backed off the ramp and then re-engaged to the ramp at the next disk location.

<FIG> is a perspective view illustrating an actuator subsystem in a reduced-head hard disk drive (HDD), <FIG> is an isolated perspective view illustrating the actuator subsystem of <FIG>, and <FIG> is an isolated plan view illustrating the actuator subsystem of <FIG>, presented as background information but not according to the invention. <FIG> collectively illustrate an actuator subsystem comprising a low profile ball screw cam assembly <NUM> (or "cam <NUM>"), which transforms rotary motion into linear motion, with a stepper motor <NUM> (or "stepping motor") disposed therein to form an actuator elevator subassembly, which is disposed within the actuator pivot and pivot bearing of the actuator subsystem (e.g., the "pivot cartridge") and is configured to vertically translate at least one actuator arm <NUM> (see, e.g., arm <NUM> of <FIG>) along with a respective HGA <NUM> (see, e.g., HGA <NUM> of <FIG>). According to an embodiment, the actuator subsystem for a reduced-head HDD consists of two actuator arm <NUM> assemblies each with a corresponding HGA <NUM> (e.g., a modified HSA, in which the actuator arm assemblies translate vertically, or elevate, while the VCM coil <NUM> may be fixed in the vertical direction) housing a corresponding read-write head 207a (see, e.g., read-write head 110a of <FIG>). Generally, the term "reduced-head HDD" is used to refer to an HDD in which the number of read-write heads is less than the number of magnetic-recording disk media surfaces.

With respect to electrical signal transmission, <FIG> further illustrate a flexible cable assembly <NUM> ("FCA <NUM>"), which is configured to comprise a dynamic vertical "loop" 208a ("FCA vertical loop 208a") for vertical translation of the end(s) that are coupled to the actuator elevator subassembly and/or another portion of the actuator subsystem. This FCA vertical loop 208a is in addition to a typical dynamic horizontal loop for horizontal translation purposes for when the actuator to which one end is connected is rotating. The actuator subsystem further comprises at least one connector housing <NUM> for housing an electrical connector for transferring electrical signals (e.g., motor power, sensor signals, etc.) between the actuator elevator subassembly and a ramp elevator assembly (described in more detail elsewhere herein).

With respect to actuator arm locking, <FIG> further illustrate an arm lock subsystem <NUM>, coupled with or constituent to a coil support assembly <NUM>, configured to mechanically interact with an outer diameter crash stop <NUM> ("ODCS <NUM>") to lock and unlock the actuator elevator subassembly, as described in more detail elsewhere herein.

One approach to a LUL ramp in the context of a reduced-head HDD may be to employ a traditional static ramp. <FIG> is a perspective view illustrating an elevator ramp assembly, and <FIG> is a perspective view illustrating a similar elevator ramp assembly (having a slight variation in the motor carriage configuration), presented as background information but not according to the invention. The elevator ramp assembly or ramp mechanism illustrated is positioned generally in the area of A-A (<FIG>) and comprises a multi-disk ramp <NUM> and a single ramp adapter <NUM> coupled to a stepper motor carriage <NUM> of a stepper motor <NUM>. Thus, the stepper motor <NUM> drives the vertical translation of the ramp adapter <NUM>, so that the ramp adapter <NUM> can be moved, synchronously or asynchronously, in conjunction with an actuator elevator subassembly of an actuator subsystem (see, e.g., <FIG>), such that the ramp adapter <NUM> can mate with a desired "level" of the ramp <NUM>. Each level of the ramp <NUM> corresponds to a respective disk-ramp portion <NUM>10a-310n of the ramp <NUM> (where n is a number that may vary from implementation to implementation based on the number of disks in a given HDD), which corresponds to the position of a respective disk <NUM> when installed in an HDD. When the ramp adapter <NUM> reaches the desired level of the ramp <NUM>, then the head-stack assembly (HSA) can be driven by the VCM (see, e.g., the VCM of <FIG>) to engage with the ramp adapter <NUM> and then with the appropriate level of the ramp <NUM>, such that the HSA can ultimately be loaded to an operational position relative to the desired disk of the multi-disk stack.

The drive mechanism for the ramp adapter <NUM> comprises the stepper motor <NUM> with carriage <NUM> (<FIG>), 313a (<FIG>), a lead screw <NUM> with which the carriage <NUM> is translatably coupled, and a support or guide rail <NUM>. As the ramp adapter <NUM> is fixedly coupled with the stepper motor carriage <NUM>, 313a, the ramp adapter <NUM> is driven by the rotation of the lead screw <NUM> under the control of the stepper motor <NUM>.

A proximity sensing subassembly, for ramp adapter <NUM> position sensing and driver feedback purposes, is configured to sense the Z-position (e.g., vertical height) of the carriage <NUM>, 313a and thus the ramp adapter <NUM>. The type/form of sensing mechanism used may vary from implementation to implementation. For example, according to an embodiment, sensing is based on the position of the carriage <NUM>, 313a and the ramp adapter <NUM> relative to a magnetic encoding strip and, ultimately, relative to the disk stack. The proximity sensing subassembly comprises a magnetic encoder strip <NUM> located proximally to at least one corresponding position sensor <NUM> mounted on the carriage <NUM>, 313a. According to an embodiment, one or more Hall effect sensors are implemented for the position sensor(s) <NUM>, which function in coordination with the closely-positioned magnetic encoder strip <NUM> mounted on a support structure or stiffener. Generally, a Hall effect sensor (or simply "Hall sensor") measures the magnitude of a magnetic field, where the output voltage of the sensor is proportional to the magnetic field strength through the sensor. In other embodiments, other magnetic or non-magnetic based sensing mechanisms may be used for position detection (see, e.g., the inductive sensing mechanism of <FIG>). A flexible cable assembly (FCA) <NUM> comprising a vertical "loop" or slack, may be implemented to carry the electrical signals from the position sensor(s) <NUM> to an electrical connector on connecter housing <NUM> and onward to some form of controller electronics.

A fixed load/unload (LUL) ramp, such as ramp <NUM> (<FIG>), interfaces with each disk of a multi-disk stack simultaneously, which would therefore require more material (e.g., plastic) to form the multi-level ramp. Thus, it is not considered cost-efficient to have such a multi-level ramp if only one disk needs to be accessed at a time, and a multi-level ramp inhibits the ability to introduce tighter disk spacing within the disk stack.

<FIG> is a perspective view illustrating a rotatable ramp assembly, presented as background information but not according to the invention. Rotatable ramp assembly <NUM> or ramp mechanism comprises a base <NUM>, on which a rotating latch link <NUM> is coupled. Rotating latch link <NUM> is configured for rotation (counter-clockwise) about axis 404a by physical interaction with a part of the head stack assembly (HSA), such as by interaction with actuator arm <NUM> (see, e.g., <FIG>). The latch link <NUM> is mechanically coupled with a rotating ramp holder <NUM>, to which a LUL ramp <NUM> is coupled. Note that the ramp holder <NUM> and ramp <NUM> may be integrated together and formed as a unitary structure, i.e., a single part. As the latch link <NUM> is driven to rotate counter-clockwise, ramp holder <NUM> and ramp <NUM> are driven to overcome magnetic attraction between a magnet <NUM> fixed to the ramp holder <NUM> and a latch stop <NUM>, and to rotate clockwise up to a point of contact with the latch stop <NUM>, thereby moving the ramp <NUM> in and out of engagement with a disk of a multi-disk stack.

<FIG> is a top view illustrating the rotatable ramp assembly of <FIG> in a first operational state within a hard disk drive, and <FIG> is a top view illustrating the rotatable ramp assembly of <FIG> in a second operational state within a hard disk drive, both presented as background information but not according to the invention;. The operational state depicted in <FIG> shows the LUL ramp assembly <NUM>, positioned generally in the area of A-A (<FIG>), engaged with a disk (see, e.g., recording medium <NUM> of <FIG>) of a multi-disk stack, whereby a distal end of the ramp <NUM> is positioned so that the outer perimeter of the disk <NUM> is disposed within a channel at the distal end of the ramp <NUM>, and with the HSA shown parked on the ramp <NUM>. As such, the ramp holder <NUM> is latched or temporarily fixed by the magnetic attraction between the magnet <NUM> and the latch stop <NUM>. This first operational state of the rotatable ramp assembly <NUM> allows the HSA to be loaded onto a disk for various seek/read/write operations to be performed by the HSA under the control of the VCM. The operational state depicted in <FIG> shows the LUL ramp assembly <NUM> disengaged from a disk <NUM> of a multi-disk stack, whereby the distal end of the ramp <NUM> is positioned so that the outer perimeter of the disk <NUM> is free of (i.e., not disposed within) the channel at the distal end of the ramp <NUM>, and with the HSA shown removed from the ramp <NUM>, in response to a sufficient force applied by the actuator arm <NUM> to the latch link <NUM>. As such, the ramp holder <NUM> is unlatched from the magnetic attraction of the latch stop <NUM> with the magnet <NUM>, and in a rotated position with the ramp <NUM> tip off the disk surface. This second operational state of the rotatable ramp assembly <NUM> allows for disk seek operations (i.e., disk-to-disk translation operations) of the HSA under the control of the actuator elevator subassembly comprising the cam <NUM> and in-pivot stepper motor <NUM> (<FIG>), according to an embodiment. Likewise, the second operational state of the rotatable ramp assembly <NUM> allows for vertical translation of the ramp assembly <NUM>, such as described in more detail in reference to <FIG>. In response to removal of the force applied by the actuator arm <NUM> to the latch link <NUM>, the ramp holder <NUM> latches again by way of the magnetic attraction between the magnet <NUM> and the latch stop <NUM>, that is, the magnetic attraction between the magnet <NUM> and the latch stop <NUM> is sufficiently strong to pull the ramp <NUM> back into the disk <NUM> area when the actuator arm <NUM> recedes from contact with the latch link <NUM>.

<FIG> is a perspective view illustrating a vertically translatable rotatable ramp assembly within a hard disk drive, presented as background information but not according to the invention. The translatable ramp assembly illustrated comprises a ramp assembly (similar to rotatable ramp assembly <NUM>, with like-numbered parts configured and operable the same as or similarly to how described in reference to <FIG>) or ramp mechanism, positioned generally in the area of A-A (<FIG>), including a plurality of structural interfaces 402a for coupling with a lead screw <NUM>, configured to be driven by a stepper motor <NUM>, and at least one guide rail <NUM>. The stepper motor <NUM> drives the vertical translation of the ramp assembly <NUM> so that the ramp <NUM> can be moved, when in the second operational state illustrated in <FIG>, in conjunction with an actuator elevator subassembly of an actuator subsystem (see, e.g., <FIG>), such that the ramp <NUM> can mate with a desired disk <NUM> of a multi-disk stack. When the ramp <NUM> reaches the desired level of the disk stack, then the head-stack assembly (HSA) can be driven by the VCM (see, e.g., the VCM of <FIG>) to engage with the ramp <NUM> such that the HSA can ultimately be loaded to an operational position relative to the desired disk of the multi-disk stack, such as with the first operational state illustrated <FIG>. According to an embodiment, at least one of the interfaces 402a, such as an interface 402a associated with the base <NUM> and/or the latch link <NUM>, comprises a bushing. According to another embodiment, at least one of the interfaces 402a, such as an interface 402a associated with the base <NUM> and/or the latch link <NUM>, comprises a linear bearing.

A similar proximity sensing subassembly such as illustrated and described in reference to <FIG> (not shown here, for drawing simplicity and clarity) may be implemented for ramp <NUM> and/or ramp assembly <NUM> position sensing and driver feedback purposes, and configured to sense the Z-position (e.g., vertical height) of the ramp <NUM> relative to a magnetic encoder strip and, ultimately, relative to the disk stack. That is, according to an embodiment a proximity sensing subassembly may comprise a magnetic encoder strip (e.g., magnetic encoder strip <NUM> of <FIG>) located proximally to at least one corresponding position sensor (e.g., position sensor(s) <NUM> of <FIG>) mounted on the ramp assembly <NUM>.

<FIG> is a perspective view illustrating a vertically translatable articulated ramp assembly in a first operational state, and <FIG> is a perspective view illustrating the articulated ramp assembly of <FIG> in a second operational state, both according to an embodiment. The articulated ramp assembly <NUM> or ramp mechanism, positioned generally in the area of A-A (<FIG>), comprises a lever portion <NUM> or member and a ramp portion <NUM> or member coupled together in a substantially normal relative positioning (although normal relative positioning is not required). The lever portion <NUM> and the ramp portion <NUM> are coupled with a plurality of interconnected structural elevator interfaces <NUM> via a plurality of flexures <NUM>, which act like cantilevered spring beams. At least one of the elevator interfaces <NUM> is movably coupled with a lead screw <NUM>, which is configured for driving by a stepper motor <NUM>, while the other elevator interface(s) is movably coupled with a respective guide rail <NUM>. The lever portion <NUM> is configured for translation by physical interaction with a part of the head stack assembly (HSA), such as by interaction with actuator arm <NUM> (see, e.g., <FIG>).

<FIG> illustrates the articulated ramp assembly <NUM> in a first operational state within a hard disk drive, and <FIG> illustrates the articulated ramp assembly in a second operational state within a hard disk drive. The operational state depicted in <FIG> shows the articulated assembly <NUM> engaged with a disk (see, e.g., recording medium <NUM> of <FIG>) of a multi-disk stack, whereby a distal end of the ramp portion <NUM> is positioned so that the outer perimeter of the disk <NUM> is disposed within a channel at the distal end of the ramp portion <NUM>, and with the HSA shown parked on the ramp <NUM>. This first operational state of the articulated ramp assembly <NUM> allows the HSA to be loaded onto a disk for various seek/read/write operations to be performed by the HSA under the control of the VCM.

The operational state depicted in <FIG> shows the articulated ramp assembly <NUM> disengaged from a disk <NUM> of a multi-disk stack, whereby the distal end of the ramp <NUM> is positioned so that the outer perimeter of the disk <NUM> is free of (i.e., not disposed within) the channel at the distal end of the ramp <NUM>. As the lever portion <NUM> is driven to translate rightward, the flexures <NUM> are flexed (e.g., in a state of spring tension) and the interconnected ramp portion <NUM> is likewise driven rightward, thereby moving the ramp portion <NUM> out of engagement with a disk of a multi-disk stack. As such, the ramp portion <NUM> is in a translated position with the ramp tip off the disk surface. This second operational state of the articulated ramp assembly <NUM> allows for disk seek operations (i.e., disk-to-disk translation operations) of the HSA under the control of the actuator elevator subassembly comprising the cam <NUM> and in-pivot stepper motor <NUM> (<FIG>), according to an embodiment. Likewise, the second operational state of the articulated ramp assembly <NUM> allows for vertical translation of the ramp assembly <NUM>, such as described in more detail elsewhere herein.

Note that the illustrations of <FIG> depict the flexures <NUM> in a relaxed or neutral position when the ramp portion <NUM> is engaged with the disk <NUM>, and in a flexed position (e.g., in a state of spring tension) when the ramp portion <NUM> is disengaged from the disk <NUM>. However, this arrangement may vary from implementation to implementation, as the articulated ramp assembly <NUM> may be configured so that the flexures <NUM> are in a relaxed or neutral position when the ramp portion <NUM> is disengaged from the disk <NUM> and in a flexed position when the ramp portion <NUM> is engaged with the disk <NUM>.

Similarly to the rotatable ramp assembly <NUM> (see, e.g., <FIG>), the articulated ramp assembly <NUM> is considered a vertically translatable articulated ramp assembly within a hard disk drive, according to an embodiment, in view of the plurality of structural elevator interfaces <NUM> configured for coupling with a lead screw <NUM>, configured to be driven by a stepper motor <NUM>, and at least one guide rail <NUM>. The stepper motor <NUM> drives the vertical translation of the ramp assembly <NUM> so that the ramp portion <NUM> can be moved, when in the second operational state illustrated in <FIG>, in conjunction with an actuator elevator subassembly of an actuator subsystem (see, e.g., <FIG>), such that the ramp portion <NUM> can mate with a desired disk <NUM> of a multi-disk stack. When the ramp portion <NUM> reaches the desired level of the disk stack, then the head-stack assembly (HSA) can be driven by the VCM (see, e.g., the VCM of <FIG>) to engage with the ramp portion <NUM> such that the HSA can ultimately be loaded to an operational position relative to the desired disk of the multi-disk stack, such as with the first operational state illustrated <FIG>. As with the rotatable ramp assembly <NUM>, at least one of the elevator interfaces <NUM> may comprise a bushing and/or at least one of the elevator interfaces <NUM> may comprise a linear bearing.

While a similar proximity sensing subassembly such as illustrated and described in reference to <FIG> may be implemented for ramp assembly <NUM> position sensing and driver feedback purposes, and configured to sense the Z-position (e.g., vertical height) of the ramp portion <NUM> relative to a magnetic encoder strip, according to an embodiment a sensor <NUM> is coupled with a portion of the ramp assembly <NUM> and positioned as illustrated in <FIG> in order to directly sense the location of the disk edge, rather than sensing the position based on an object remote from the disk stack (e.g., a magnetic encoder strip). According to an embodiment, a non-contact inductive proximity sensor, and associated electronic circuitry 508a, is utilized for sensor <NUM> and is positioned as close to the disk stack as practically feasible. As such, inductive sensor <NUM> relies on the principle of electromagnetic induction and is implemented in the form of one or more coils embedded in a flexible printed circuit (FPC) and/or flexible cable assembly such as a portion of or an electrical extension of FCA <NUM>, which may ultimately tie in with FCA <NUM> (<FIG>). In one form of inductive sensor <NUM>, a coil (e.g., an inductor, such as in an LCR circuit comprising an inductor, capacitor, and resistor) may be used to generate a varying magnetic field and another coil may be used to detect changes in the magnetic field introduced by a metallic object, such as the nickel-plating covering the edge of disk <NUM>. In another form of inductive sensor <NUM>, a metallic object (such as the nickel-plating covering the edge of disk <NUM>) moving past the coil(s) will alter the inductance in the coil and hence the resonant frequency of the LCR circuit electrically coupled to the electronic circuitry 508a, whereby the change in resonant frequency is detected. The electronic circuitry 508a then converts this change in resonant frequency to a standard DAC (digital-to-analog converter) output, which can be used for servo control of the stepper motor <NUM>. Hence, the change in resonant frequency of the inductive sensor <NUM>, when moving from media to air gap to media, can be detected and, therefore, the positioning of the ramp assembly <NUM> relative to the disk stack can likewise be determined. The type/form of sensing mechanism used may vary from implementation to implementation.

In the foregoing description, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Therefore, various modifications and changes may be made thereto. Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims. Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claim 1:
A vertically-translatable load/unload, LUL, ramp system for a reduced-head hard disk drive, HDD, the system comprising a ramp assembly (<NUM>),
wherein the ramp assembly (<NUM>) comprises:
a translatable LUL ramp member (<NUM>);
characterized by a translatable lever member (<NUM>) coupled with the LUL ramp member (<NUM>) and configured for mechanical interaction with a head-stack assembly, HSA;
a plurality of interconnected structural elevator interfaces (<NUM>) coupled with the LUL ramp member (<NUM>); and
a plurality of flexures (<NUM>) interconnecting the elevator interfaces (<NUM>) with the LUL ramp member (<NUM>),
wherein the ramp assembly (<NUM>) has a first operational state and a second operational state;
wherein, in the first operational state:
a zero or negligible force is applied to the lever member (<NUM>) by the HSA; and
a distal end of the LUL ramp member (<NUM>) is positioned such that an outer perimeter of a recording disk (<NUM>) of an HDD is disposed within a channel at the distal end of the LUL ramp member (<NUM>); and
wherein, in the second operational state :
a sufficient force is applied to the lever member (<NUM>) by the HSA; and
a distal end of the LUL ramp member (<NUM>) is positioned such that an outer perimeter of a recording disk (<NUM>) of an HDD is free of a channel at the distal end of the LUL ramp member (<NUM>).