Dynamic magnetic information storage or retrieval – Head mounting – For shifting head between tracks
Reexamination Certificate
2000-02-29
2002-10-29
Nguyen, Hoa T. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
For shifting head between tracks
Reexamination Certificate
active
06473270
ABSTRACT:
FIELD OF THE INVENTION
This application relates generally to the field of disc drive storage devices, and more particularly, to an apparatus and method for mitigating shock and reduce damage to the actuator assembly and other components in the disc drive.
BACKGROUND OF THE INVENTION
Disc drives are data storage devices that store digital data in magnetic form on a rotating storage medium, such as a disc. Modern disc drives comprise one or more rigid discs that are coated with a magnetizable medium and mounted on the hub of a drive motor for rotation at a constant high speed. Information is stored on the discs in a plurality of concentric circular tracks typically by an array of transducers (“heads”) each mounted on a slider. Each slider is supported on a flexure attached to an actuator arm which is part of an actuator assembly that moves the head relative to the discs. Each transducer, e.g., a magnetoresistive read or write head, is used to transfer data between a desired track and an external environment. During a write operation, the write head writes the data onto the disc track, and during a read operation, the read head senses the data previously written on the disc track and transfers the information to a disc drive circuit board in the external environment.
The slider with the heads are mounted via flexures at the end of an actuator arm that projects radially outward from an actuator body in the actuator assembly. The actuator body pivots about a bearing assembly mounted on a base plate at a position closely adjacent to the outer extreme of the discs. The head(s) read data and transfer it through conductors on the actuator arm to a preamplifier which amplifies the signals coming from the heads.
Typically, the actuator assembly includes a voice coil motor to position the heads with respect to recording tracks on the disc surfaces. The actuator voice coil motor includes a coil mounted to the actuator body opposite the actuator arm and is immersed in the magnetic field of a magnetic circuit comprising one or more permanent magnets and magnetically permeable pole pieces. When controlled direct current (DC) is passed through the coil, an electromagnetic field is set up which interacts with the magnetic field of the magnetic circuit to cause the coil to move in accordance with the well-known Lorentz relationship. As the coil moves, the actuator body and arm pivot about the bearing assembly and the heads move across the disc surfaces. When the disc drive is stationary, the voice coil motor pivots the actuator arm, flexure, and slider away from the disc and parks the slider on a load ramp attached to the base plate adjacent to the outer diameter of the disc. Alternatively, the slider may be parked in a loading zone on the outer perimeter of the disc.
The flexure includes a load beam and a gimbal insert. One end of the load beam is attached to an end of the actuator arm opposite of the actuator body. The other end of the load beam is connected to the gimbal insert. The gimbal insert in turn is attached to and supports the slider. The physical connection between the gimbal insert and the load beam is essential for maintaining a slider flying height which will allow the heads to read and write data to and from the disc.
Mechanical shock events caused by an impact to a computer may cause permanent damage to a hard disc drive. Shock events often cause damage to the flexure and associated slider. Specifically a shock event which occurs while the disc is stationary causes deflection of the actuator arm and attached flexure which in turn may cause elements of the actuator assembly to be permanently damaged such that the recording heads loose their ability to function.
SUMMARY OF THE INVENTION
Against this backdrop the present invention has been developed to solve the above and other problems by using a snubber in a disc drive to reduce deflective movement of the actuator assembly.
A head disc assembly in a disc drive has a base plate and a top cover which encloses a drive motor, a disc supported thereon, and an actuator assembly. The actuator assembly has an actuator arm attached to one end of a flexure, and a slider or read/write head attached proximate to an opposite end of the flexure. A snubber is fastened to a stationary portion of the head disc assembly and has a snubber body and two or more snubber arms connected to the snubber body. The adjacent snubber arms form slots therebetween. As the actuator assembly pivots towards an outer diameter of the disc, a portion of the actuator assembly is inserted into each of the slots. While the actuator assembly is located within the slots, the snubber arms reduce the deflective movement of the actuator assembly during a mechanical shock event. By reducing the deflective movement, the chances of permanently damaging the actuator assembly and other disc drive components are likewise reduced.
These and various other features as well as advantages which characterize the present invention will be apparent from a reading of the following detailed description and a review of the associated drawings.
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Barina Jeff Gerard
Blakeslee Bruce L.
Haas Robert Terry
Kazmierczak Frederick Frank
McDonald Ted Randal
Merchant & Gould P.C.
Nguyen Hoa T.
Seagate Technologies LLC
Stoll-DeBell Kirstin
Watko Julie Anne
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