Abstract: An approach to a head gimbal assembly (HGA), such as for a hard disk drive, includes a swage plate assembly coupling a suspension to one side of an actuator arm, where the swage plate assembly includes a baseplate having a through-hole and a swage boss insert comprising a flange and a swage boss extending from the flange through the baseplate through-hole. The HGA is configured such that the baseplate is positioned between the flange and the actuator arm, such that a distal surface of the flange is the surface closest to a corresponding recording medium, whereby the thickness of the suspension is effectively recessed within the material dimensional buildup of the other parts and a greater clearance is provided between the suspension and the recording medium.

Abstract: Disk drive suspension baseplates made of a base metal and methods for manufacturing disk drive suspension baseplates having boss outer surfaces characterized by roughness parameters Ra?0.15 ?m.

Abstract: An assembly method between a part made of metal material and a part made of organic matrix composite material, said method having a step of providing two parts, each including a surface to be welded, and the surface to be welded of said composite part is made up, at least partially, of an exposed portion of at least one metal insert which is partially embedded in said composite part; positioning said surfaces to be welded opposite and separated from each other; and projecting, at high speed, the surface to be welded of the metal part or the exposed portion of the metal insert, onto one another, to obtain high-speed clamping to one another and to obtain a weld between the exposed portion of the metal insert of the composite part and the complementary portion of the surface to be welded.

Abstract: According to an embodiment, a head stack assembly includes an arm including a swaged seat surface with swaged hole, a load beam supporting a head, and a baseplate secured to a proximal end portion of the load beam, including an annular protrusion secured to the swaged hole of the arm by swaging, and secured to the swaged seat surface. The arm includes a distal end portion located on a longitudinal end side of the arm with respect to the center of the swaged hole and being less rigid than the other portion of the arm around the swaged hole.

Abstract: A head stack assembly comprising an actuator arm having an aperture therein, a head suspension assembly comprising a load beam having a mounting region with a aperture therein, and a base plate adapted to attach the head suspension assembly to the actuator arm, with the base plate comprising a boss tower having an outside surface and a swaging hole. One of the actuator arm aperture, the boss tower outside surface or the swaging hole is non-circular to provide increased compression between the boss tower and the actuator arm aperture in the roll direction than in the pitch direction. Methods of making a boss tower are also provided.

Abstract: A head stack assembly comprising an actuator arm having an aperture therein, a head suspension assembly comprising a load beam having a mounting region with a aperture therein, and a base plate adapted to attach the head suspension assembly to the actuator arm, with the base plate comprising a boss tower having an outside surface and a swaging hole. One of the actuator arm aperture, the boss tower outside surface or the swaging hole is non-circular to provide increased compression between the boss tower and the actuator arm aperture in the roll direction than in the pitch direction. Methods of making a boss tower are also provided.

Abstract: A mount plate includes a flange having a first surface and an opposing second surface and a boss tower having a swage hole and extending from an area where the boss tower meets the first surface of the flange to an end surface of the boss tower. The boss tower has an inner diameter defining an inner surface of the swage hole, an outer diameter defining a portion of an outer surface of the boss tower and at least one cut-out portion formed in the boss tower along an obliquely angled plane. The cut-out portion intersects with the outer surface at a first area located a first distance from where the boss tower meets the first surface of the flange and intersects with the end surface at a second area located a second distance from the inner diameter. The first distance is less than the second distance.

Abstract: A method of attaching a head assembly having an annular hollow boss to an arm having a through hole of a carriage is provided. The head assembly includes a load beam of a head suspension and a base plate fixed to a base part of the load beam. The boss is formed on the base plate. The method includes steps of, inserting the boss into the through hole, thereby setting the head assembly to the arm of the carriage, supplying lubricant along the cylindrical jig to the caulking ball and pushing the caulking ball with the cylindrical jig to pass the caulking ball through an inside of the boss and diametrally expand and plastically deform the boss, thereby fixedly fitting the boss of the head assembly to the through hole of the arm of the carriage. The method causes no deformation of a flange formed on the base plate during caulking and is achievable at low cost.

Abstract: A method of attaching a head assembly having an annular hollow boss to an arm having a through hole of a carriage is provided. The head assembly includes a load beam of a head suspension and a base plate fixed to a base part of the load beam. The boss is formed on the base plate. The method includes steps of, inserting the boss into the through hole, thereby setting the head assembly to the arm of the carriage, supplying lubricant along the cylindrical jig to the caulking ball and pushing the caulking ball with the cylindrical jig to pass the caulking ball through an inside of the boss and diametrally expand and plastically deform the boss, thereby fixedly fitting the boss of the head assembly to the through hole of the arm of the carriage. The method causes no deformation of a flange formed on the base plate during caulking and is achievable at low cost.

Abstract: A cylindrical boss portion is press-formed on a baseplate of a disk drive suspension. The boss portion is penetrated by a ball insertion hole relative to the thickness of the baseplate. The baseplate is formed of stainless steel. A chemically-polished surface is formed on an inner circumferential wall of the ball insertion hole by chemically polishing the baseplate after heat-treating it. The boss portion is inserted into a mounting hole of an actuator arm. A ball having a diameter larger than the inside diameter of the ball insertion hole is passed through the ball insertion hole. As the diameter of the boss portion is enlarged by the ball, the boss portion is fixed to the actuator arm.

Abstract: Swaging a suspension base plate to an actuator arm for a hard disk drive. A portion of material adjacent to a hole in the actuator arm is removed to create an opening to receive material. A flange of the suspension base plate is inserted into the hole in the actuator arm. The suspension base plate is swaged to the actuator arm, wherein the swaging causes material from the suspension base plate to flow into the opening.

Abstract: Disclosed is a method and system comprising: an alignment pin to be positioned adjacent to the boss hole (BH) of an actuator arm (AA); an actuator coupled to the alignment pin to move the alignment pin; an imaging device; and a computing device that performs operations including: commanding the imaging device to produce an image of the position of the alignment pin relative to the BH of the AA; commanding the HGA to be positioned in the AA such that the boss of the HGA is adjacent to the BH of the AA; and, based on the image, commanding the actuator to move the alignment pin such that the alignment pin is concentric relative to the BH and to move the alignment pin through an opening of the boss of the HGA such that the boss of the HGA is concentric and aligned with the BH of the AA.

Abstract: A cylindrical boss portion is press-formed on a baseplate of a disk drive suspension. The boss portion is penetrated by a ball insertion hole relative to the thickness of the baseplate. The baseplate is formed of stainless steel. A chemically-polished surface is formed on an inner circumferential wall of the ball insertion hole by chemically polishing the baseplate after heat-treating it. The boss portion is inserted into a mounting hole of an actuator arm. A ball having a diameter larger than the inside diameter of the ball insertion hole is passed through the ball insertion hole. As the diameter of the boss portion is enlarged by the ball, the boss portion is fixed to the actuator arm.

Abstract: A head suspension has a base plate including a flange. The flange has a first face attached to the carriage arm and a second face attached to an auxiliary member. A first-face contact is circumferentially formed along an outer circumferential edge of the first face of the flange, so that the first-face contact among parts of the base plate except the boss is most proximal to the carriage arm. A second-face contact is circumferentially formed along an outer circumferential edge of the second face of the flange, so that the second-face contact among parts of the base plate including the boss is most proximal to the auxiliary member. This configuration allows the auxiliary member to be correctly aligned with and attached to the second face of the flange.

Abstract: A suspension assembly with reduced total vertical thickness is provided for a data transducing system that includes a dual-stage actuation system for positioning a data transducer. A first structural element of the suspension assembly includes a plate portion and a boss tower that is connectable to a main actuator of the dual-stage actuation system. A second structural element of the suspension assembly includes a recess that receives the plate portion of the first structural element, an opening through which the boss tower extends for connection to the main actuator of the dual-stage actuation system, and a flexible region to which a microactuator element of the dual-stage actuation system is connected.

Abstract: A disk drive head stack assembly includes an actuator arm tip that includes a swaging hole centered about a swaging axis. A first suspension assembly has a first swage boss that protrudes into the swaging hole. A second suspension assembly has a second swage boss that protrudes into the swaging hole and does not contact the first swage boss. Each of the first and second swage bosses includes an inner lip that extends radially closer to the swaging axis than any other part of that swage boss. The inner lip thickness of the first swage boss, measured parallel to the swaging axis, increases more greatly with increasing radial distance from the swaging axis than does the inner lip thickness of the second swage boss.

Abstract: Interconnections for attaching a suspension assembly to an arm of an actuator or positioning device are disclosed. In illustrated embodiments, the interconnection includes one or more weld connections formed along opposed side seams of overlapping portions of the arm and head suspension assembly. In illustrated embodiments, the weld connections are formed along side surfaces generally transverse to upper and lower surfaces of the arm. In another embodiment, a groove pattern is formed, for example via a laser etching process, in an overlapping portion of the head suspension assembly or arm and an epoxy is inlayed in the groove to connect the head suspension assembly and arm. Illustrated embodiments also include multiple connections including, for example, a swage connection and a weld or other connection.

Abstract: It is an object to achieve prevention of lowering resonant frequency and improved production efficiency while achieving reduction in weight of a supporting part with a boss portion and reduction in thickness at area at which the boss portion is located. In the present invention, the supporting part includes a first supporting member with which a load bending part is connected, and a second supporting member with the boss portion and a main body region extended radially outward from the boss portion. At least one of the inner periphery of the mount hole and the outer periphery of the main body region is integrally provided with a rib region.

Abstract: A test assembly for a disk drive suspension head gimbal assembly includes a steel mount plate and a mount sub-plate of a material such as silicon carbide having a modulus of elasticity to density ratio that is significantly higher than the ratio for stainless steel. Preferably the mount plate and the mount sub-plate taken together have a first resonant shear frequency of greater than 50 KHz, which is generally greater than the frequency range of interest for testing head gimbal assemblies. The high modulus of elasticity to density ratio helps to ensure that any shear mode resonances of the test assembly occur at frequencies that are higher than the frequencies of interesting for head gimbal assembly shear resonance testing purposes.

Abstract: A method of designing a hard disk drive suspension swage hub geometry for an actuator arm having upper and lower suspensions attached thereto, includes using a finite element analysis model to simulate the effects of swaging the suspensions to the actuator arm, identifying relevant geometric parameters of the suspensions, for each suspensions performing a linear regression to fit an equation containing the geometric parameters to a normal force of the suspension to the actuator arm after swaging according to the fine element analysis, identifying a desired range of differences between the normal forces, using the desired difference range, and solving for values of geometric parameters to produce a set of target design parameters for the suspension swage hubs.

Abstract: A load bending part includes a pair of first elastic plate parts and a second elastic plate part. The pair of first elastic plate parts are elastically deformed in a bended manner so as to generate a first pressing load. The second elastic plate part is positioned between the pair of first elastic plate parts in the suspension widthwise direction in a state of having both ends in its longitudinal direction connected to a pair of support pieces of a supporting part, and are elastically deformed in a twisted manner around a twist axis line along the suspension widthwise direction so as to generate a second pressing load. The total of the first and second pressing loads functions as a load for pressing the magnetic head slider toward the disk surface against air pressure due to rotation of a disk surface.

Abstract: An apparatus for attaching one or more HGAs to an actuator assembly including one or more actuator arms comprises a set of pivoting supports corresponding to the one or more HGAs and mechanisms that pivot each of the pivoting supports between open positions and closed positions. For each of the set of pivoting supports, in the open position, a gap adjacent to the pivoting support is sufficiently large to receive both a mounting platform of one of the actuator arms and a baseplate of one of the HGAs positioned in alignment with the mounting platform of the one of the actuator arms, and, for each of the set of pivoting supports, in the closed position, the gap is sufficiently small to constrain the baseplate of the one of the HGAs against the mounting platform of the one of the actuator arms.

Abstract: A method of swaging a head gimbal assembly (HGA) to an actuator arm comprises positioning a tubular element on the HGA adjacent a hole in the actuator arm; restraining the subassembly; providing a rod formed from a shape memory alloy (SMA), the SMA having a martensitic phase at a low temperature and an austenitic phase above a phase transition temperature that is higher than the low temperature, the rod having an initial diameter that is smaller than diameters of the tubular element and the hole; extending the rod through the tubular element and hole; heating the rod above the phase transition temperature such that the rod expands to a second diameter that is greater than the initial diameter to plastically deform the HGA and swage together the HGA and actuator arm to form an assembly; cooling the rod and removing the rod from the assembly such that the rod returns to the initial diameter.

Abstract: A baseplate has a flange and a boss tower with an opening for receiving a swaging ball during a swaging process. The flange has a pre-swaging profile that compensates for swaging-induced deformation of the flange. A portion of the baseplate is clamped into a flattened configuration and the flange is mounted to a suspension. The boss tower is inserted into an opening in an actuator arm. A swaging ball is passed through the swaging opening. The pre-swaging profile compensates for forces exerted on the flange during swaging such that deformation of the baseplate due to swaging is substantially eliminated.

Abstract: In an information storage apparatus, a relatively thin attachment member has a cylindrical boss section projecting from a surface thereof and a path passing through the attachment member and reaching the extreme end of the boss section and is attached to a relatively thick base member. The base member has a through hole which passes therethrough in the thickness direction thereof and into which the boss section is inserted. The attachment member is caulked to the base member by plastically deforming the boss section by causing a caulking ball whose diameter is larger than that of the path to pass therethrough in the state that the boss section is inserted into the through hole. The through hole has an escape section into which a part of the plastically deformed boss section escapes, thereby a large amount of plastic deformation of the boss section can be suppressed.

Abstract: A method of assembling a carriage assembly is capable of suppressing deformation of spacer portions when suspensions are attached to carriage arms. The method of assembling a carriage assembly aligns fitting holes provided in front end portions of carriage arms and spacer holes provided in spacer portions of suspensions and places the suspensions onto the carriage arms, and then presses a ball with a diameter equal to or greater than an inner diameter of the spacer holes with a pressure-applying member to pass the ball through the spacer holes, thereby crimping spacer hole edge portions of the spacer portions and attaching the suspensions to the front end portions of the carriage arms. By applying ultrasonic vibration from two axial directions to the pressure-applying member, the pressure-applying member is caused to vibrate on a two-dimensional movement path on a predetermined plane and passes the ball through the spacer holes while causing the ball to rotate.

Abstract: A magnetic head supporting structure comprises a metal purified by vacuum arc remelting, vacuum induction melting, electroslag remelting, or electroslag remelting under vacuum, in at least one of the regions that undergo plastic deformation during disk drive manufacture, to reduce small hard inclusions that might be released into the disk drive interior environment.

Abstract: A baseplate for swaging a head suspension to an actuator arm includes a flange with an opening having a back bore diameter and a boss tower extending from the flange and having an outer diameter. The back bore diameter is less than or equal to about 105% of the outer diameter and greater than or equal to about 90% of the outer diameter.

Abstract: A swage mount that includes a flange, having a first side and a second side, and a cylindrically shaped hub. The hub is primarily comprised of a metal (such as stainless steel), and extends from the second side of the flange, and has an inner surface and an outer surface. The surface of the swage mount is plated with one or more layers of metal, or a combination of metals, which provide a) increased retention torque, and b) increased part cleanliness. This invention may be used in conjunction with surface hardened swage mounts that contain surface protrusions. In this case the metal plating prevents separation of the protrusions from the swage mount, thereby preventing contamination.

Abstract: A disc-drive assembly including an actuator arm, a load beam and a swage mount. The actuator arm has a thickness (TA), an arm tip with a width (WA), and arm-hole with a diameter (DA) in the actuator arm. The load beam has a load beam hole. The swage mount has a flange with a width (WF). The swage mount has a hub with an outer hub diameter (DOD), extending from the one side of the flange. The outer hub diameter (DOD) of the hub is less than 2.54 mm. The flange width (WF) divided by the hub outer diameter is greater than 2.0. The ratio of the outer hub diameter (DOD) to the actuator arm thickness (TA) is less than 1.5, and the ratio of the diameter of the arm hole (DA) to the width of the arm tip (WA) is less than 0.5.

Abstract: A method of making a multi-piece head suspension for a rigid disk drive. The method includes providing a first layer including a mounting region with an integral boss tower attached to a stiffener by one or more positioning tabs; attaching a second layer including a spring region to an interface between the mounting region and the stiffener; attaching a flexure to the stiffener; and removing the positioning tabs. The flexure can optionally be a portion of the second layer.

Abstract: A head actuator is made thinner without sacrificing its strength to thereby achieve the thinning of a hard disk apparatus. On the base end of each of two suspensions is provided a boss that protrudes in the direction of the side on which a magnetic head is provided, and a suspension fixing section having a hole into which the bosses are inserted is formed towards the tip of an arm. The boss of one of the suspensions is inserted into the hole from the upper end section thereof, and the boss of the other suspension is inserted into the hole from the lower end section thereof. Thus, the arm is fixed in place by being held by the two suspensions from above and below.

Abstract: A base plate adapted to attach a head suspension assembly to an actuator arm. The base plate includes a flange portion with a boss tower perpendicular to a plane of the flange portion. The boss tower includes a swaging hole with a tapered portion that increases in diameter in a direction away from the flange portion.

Abstract: A baseplate for swaging a disk drive head suspension to an arm having a thickness and a neutral axis. The baseplate includes a boss tower having an outer diameter high point configured to be located within about ±6% of the arm thickness from the neutral axis when swaged to an arm.

Abstract: A head stack assembly for use in a disk drive. The head stack assembly includes an actuator body. The head stack assembly further includes an actuator arm extending from the actuator body. The actuator arm includes an arm tip portion. The head stack assembly further includes a suspension attached to the arm tip portion. The head stack assembly further includes a laminated nut plate attached to the arm tip portion and the suspension. The nut plate includes first and second metal layers and a damping layer interposed between the first and second metal layers for mitigating vibration of the suspension with respect to the actuator arm.

Abstract: A head suspension for a disk drive has a load beam, a base plate, and a recess. The base plate has a thin flange and is capable of improving the attaching accuracy and strength of the head suspension to a carriage arm of the disk drive. The base plate has the flange and a boss. The flange has a contact face to be attached to a contact face of the carriage arm. The boss is inserted into a hole of the carriage arm and plastically deformed therein to fix the base plate to the carriage arm. The load beam has a rigid part and a resilient part and is supported by the base plate, to apply load on a slider arranged at a front end of the load beam. The recess is formed on the base plate along a corner between the flange and the boss, to secure a gap relative to the contact face of the carriage arm.

Abstract: A head suspension for a disk drive includes a plate that is easily and correctly be attached to a carriage of the disk drive and improves the attaching accuracy and strength of the head suspension to the carriage. The head suspension includes the plate and a load beam. The plate has a boss that is formed separately from the plate. The boss has a base fixed to the plate and a protrusion fitted into a hole of a carriage arm of the carriage. The plate has a through hole. The base of the boss is fitted into the through hole and is fixed to the plate. Under this state, the protrusion of the boss protrudes from a first face of the plate, and the base of the boss protrudes from a second face of the plate. An end face of the base of the boss serves as a contact face for jig.

Abstract: A method of making a multi-piece head suspension for a rigid disk drive. The method includes providing a first layer including a mounting region with an integral boss tower attached to a stiffener by one or more positioning tabs; attaching a second layer including a spring region to an interface between the mounting region and the stiffener; attaching a flexure to the stiffener; and removing the positioning tabs. The flexure can optionally be a portion of the second layer.

Abstract: A method for detaching a suspension assembly adapted to support a head staked to an actuator arm of an actuator block of a disc drive. The method includes the steps of inserting an expandable device having an expandable flanged end, expanding a dimension of the inserted flanged end and moving the device to release the suspension assembly staked to the actuator arm.

Abstract: A swage mount for a recording head suspension comprising a flange, and a hub made of a base metal extending from the flange, and at least an outer surface of the hub is plated with one or more layers of metal which provides increased retention torque, and/or increased cleanliness, and/or increased corrosion resistance. This invention may be used in conjunction with swage mounts that contain surface protrusions that are intentionally created (such as chromium nitride or chromium carbide protrusions) or not intentionally created (such as material inclusions or embedded media particles). In this case the metal plating helps prevent separation of the protrusions from the swage mount, thereby helping to prevent contamination.

Abstract: Provided is a component for use in swage mounting that includes a base plate, having a first side and a second side, and a hub which preferably is cylindrically shaped. The hub is primarily comprised of a first material (such as stainless steel), extends from the second side of the base plate, and has an inner surface and an outer surface. The outer surface of the hub includes numerous protrusions that are less than approximately 50 microns in height and that are primarily comprised of a second material (such as a carbide or a nitride) which is different from the first material. Preferably, the protrusions are substantially harder (such as at least 50 hardness Vickers harder) than the base material.

Abstract: A head actuator is made thinner without sacrificing its strength to thereby achieve the thinning of a hard disk apparatus. On the base end of each of two suspensions is provided a boss that protrudes in the direction of the side on which a magnetic head is provided, and a suspension fixing section having a hole into which the bosses are inserted is formed towards the tip of an arm. The boss of one of the suspensions is inserted into the hole from the upper end section thereof, and the boss of the other suspension is inserted into the hole from the lower end section thereof. Thus, the arm is fixed in place by being held by the two suspensions from above and below.

Abstract: A head suspension assembly in a rigid disk drive having a load beam with a mounting region, a rigid region and a spring region located between the mounting region and rigid region. The mounting region includes an integral boss tower having attachment features. A method of making a multi-piece head suspension for a rigid disk drive is also disclosed. The method includes providing a first layer including a mounting region with an integral boss tower attached to a stiffener by one or more positioning tabs; attaching a second layer including a spring region to an interface between the mounting region and the stiffener; attaching a flexure to the stiffener; and removing the positioning tabs. The flexure can optionally be a portion of the second layer.

Abstract: A method for swaging a suspension assembly to an actuator arm of a data storage device is disclosed. The method includes steps of inserting a deformable tubular stake into an aperture of an actuator arm and inserting an expandable swaging member into a channel of the tubular stake within the aperture of the actuator arm. Thereafter, the method includes the step of expanding the swaging member to deform the tubular stake to swage the tubular stake to the actuator arm of the data storage device.

Abstract: The present invention provides a baseplate comprising a cylindrical hub, a flat flange, and one or two circular notches of a “V” or “U” shape etc. formed in said flange. This baseplate has the advantages of smaller deformation and larger retention torque during swage operation. Also it is easy to make and has no further cost in production. Moreover, the present invention further provides an arm and suspension assembly equipped with the baseplate and a hard disk drive equipped with the arm and suspension assembly.

Abstract: A head suspension for a disk drive has a base plate (19) to be attached to a carriage of the disk drive and a load beam (21) consisting of a rigid part (27) and a resilient part (29), to apply load onto a slider. The rigid part and resilient part are separately formed. The rigid part is joined to a first side (29a) of the resilient part. The suspension also has a reinforcing plate (37) to hold and fix a second side (29b) of the resilient part between the reinforcing plate and the base plate. The base plate stably and resiliently supports the load beam. This suspension satisfies required characteristics.

Abstract: A method of bonding a magnetic disk drive head suspension to an actuator arm. The actuator arm has a boss hole therein and the suspension includes a base plate with an inside diameter or barrel therein. A thermoplastic cylindrical core is fabricated with a barrel therein. The suspension and actuator arm are clamped together to form a head stack assembly in which the base plate inside diameter is aligned with the boss hole in the actuator arm. The thermoplastic cylindrical core is passed through the base plate inside diameter and the boss hole in the actuator arm. A heating tool, such as an ultrasonic horn is passed through the barrel of the cylindrical core and heated causing the cylindrical core expand and bond to the base plate inside diameter and to the actuator arm boss hole.

Abstract: A method of attaching a load beam to a head actuator arm. A number of weld holes are provided in the load beam and the actuator arm. A thermoplastic base plate is aligned over the weld holes in the load beam and the actuator arm. A heating tool having a number of pins is clamped over the base plate such that points of the heating tool pins coincide with the number of weld holes. The heating tool is heated such that peaks of thermoplastic base plate material are extruded through the weld holes. The heating tool causes heat to be applied and focused at the points to cause the thermoplastic base plate to flow and expand into the weld holes in both the load beam and the actuator arm, thereby rigidly connecting the thermoplastic base plate and load beam to the actuator arm.

Abstract: A swage mount that includes a flange, having a first side and a second side, and a cylindrically shaped hub. The hub is primarily comprised of a metal (such as stainless steel), and extends from the second side of the flange, and has an inner surface and an outer surface. The surface of the swage mount is plated with one or more layers of metal, or a combination of metals, which provide a) increased retention torque, and b) increased part cleanliness. This invention may be used in conjunction with surface hardened swage mounts that contain surface protrusions. In this case the metal plating prevents separation of the protrusions from the swage mount, thereby preventing contamination.

Abstract: A head suspension for a disk drive has a load beam, a base plate, and a recess. The base plate has a thin flange and is capable of improving the attaching accuracy and strength of the head suspension to a carriage arm of the disk drive.