Snubber for a disc drive

Details Snubber for a disc drive Snubber for a disc drive

1998-10-30

2001-04-03

Tupper, Robert S. (Department: 2754)

Dynamic magnetic information storage or retrieval

Record transport with head stationary during transducing

Disk record

Reexamination Certificate

active

06212029

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to the field of disc drive data storage devices and more particularly, but not by way of limitation, to a snubber for supporting the outer edge of a data disc of the disc drive.
BACKGROUND OF THE INVENTION
Modern disc drives are commonly used in a multitude of computer environments, ranging from super computers to notebook computers, to store large amounts of data in a form that is readily available to a user. Typically, a disc drive has one or more magnetic discs that are rotated by a spindle motor at a constant high speed. Each disc has a data storage surface divided into a series of generally concentric data tracks that are radially spaced across a band having an inner diameter and an outer diameter. The data is stored within the data tracks on the disc surfaces in the form of magnetic flux transitions. The flux transitions are induced by an array of read/write heads. Typically, each data track is divided into a number of data sectors where data is stored in fixed size data blocks.
The read/write head includes an interactive element such as a magnetic transducer. The interactive element senses the magnetic transitions on a selected data track to read the data stored on the track. Alternatively, the interactive element transmits an electrical signal that induces magnetic transitions on the selected data track to write data to the track.
Each of the read/write heads is mounted to a rotary actuator arm and is selectively positioned by the actuator arm over a pre-selected data track of the disc to either read data from or write data to the data track. The read/write head includes a slider assembly having an air bearing surface that, in response to air currents caused by rotation of the disc, causes the head to fly adjacent to the disc surface with a desired gap separating the read/write head and the corresponding disc.
Typically, multiple center-open discs and spacer rings are alternately stacked on a spindle motor hub. The hub, defining the core of the stack, serves to align the discs and spacer rings around a common axis. Collectively the discs, spacer rings and spindle motor hub define a disc pack assembly. The surfaces of the stacked discs are accessed by the read/write heads which are mounted on a complementary stack of actuator arms which form a part of an actuator assembly. The actuator assembly generally includes head wires which conduct electrical signals from the read/write heads to a flex circuit which, in turn, conducts the electrical signals to a flex circuit connector mounted to a disc drive base deck.
When the disc drive is not in use, the read/write heads are parked in a position separate from the data storage surfaces of the discs. Typically, a landing zone is provided on each of the disc surfaces where the read/write heads are positioned before the rotational velocity of the spinning discs decreases below a threshold velocity which sustains the air bearing. The landing zones are generally located near the inner diameter of the discs.
The environment in which computers are used today is demanding. This is especially true for laptop computers which are often used while in transit. As a result, disc drives must function reliably under conditions of external shock and vibration. The external shock is quantified in terms of magnitude and duration, and disc drives are designed in accordance with specifications for operational and non-operational resistance to shocks.
Operational specifications address the levels of permissible shock while the drive is in operation. Low level shocks can cause the read/write heads to move off-track, resulting in data reading and writing errors. Non-operational specifications address the limits of shock due to handling and transit activities while the disc drive is non-operational. Non-operational shocks can cause damage to the read/write head and to the data discs.
There are at least four types of non-operational damage related to shock. Outer diameter portions of the data discs are damaged when the discs deflect and make contact with the actuator. Arm tip induced media damage can occur when the actuator arm deflects into the disc. Head induced media damage can occur when the heads impact the discs, either by the heads lifting off the media or by vibration propagating through the head arm after a shock.
Snubbers generally have been employed to limit the amount of deflection of disc drive components following a shock. Disc snubbers in particular are widely used to limit the amount of deflection of an outer edge of a disc in a disc pack. A common problem, however, with disc snubbers is associated with mechanical accumulation of tolerances. It is difficult to design a snubber which properly engages the discs through the range of mechanical tolerances which combine and stack among the numerous components in a disc drive. For example, the location of the discs is a function of base deck casting and machining tolerances, disc dimensions, top cover dimensions, spindle motor tolerances, and disc spacer dimensions. When all of these and other associated parts are joined, it is impossible to determine exactly where the edge of the disc will be located. This makes it difficult to properly position the disc snubber so as to effectively limit disc deflection.
The demand for ever-smaller disc spacings and ever-higher disc capacity has accelerated the long-felt need for a disc snubber that clearingly disengages the discs when the disc drive is operational, yet abuttingly engages the discs when the disc drive is non-operational, thus providing an improved fixed support of the disc edge to minimize deflection following an external shock.
SUMMARY OF THE INVENTION
The present invention is directed to a disc drive having a disc snubber for selectively engaging the discs of the disc drive to minimize a deflection of the disc resulting from an external shock or vibration imparted to the disc drive.
The disc snubber has a pivoting body that pivots between a first, or closed, position and a second, or open, position. An array of extending portions depend from the pivoting body, having angled surfaces which abuttingly engage the discs in the closed position of the pivoting body, and which furthermore clearingly disengage the discs in the open position of the pivoting body. In the closed position the abutting engagement of the angled surfaces provides a fixed support of the outer edge of the discs to minimize the deflection of the disc following an external shock or vibration.
The snubber has a coiled spring that operably engages and biases the pivoting body to the closed position. A solenoid, when electrically energized, opposingly urges the pivoting body to the open position against the force of the coiled spring.
A snubber constructed in accordance with the present invention provides a variable clearance between the engaging surfaces thereof and the discs. In an operable mode of the disc drive a clearance between the engaging surfaces and the spinning discs is maximized so that the discs clearingly disengage the snubber except in the event of a substantial shock that deflects a disc a significant amount. When the disc drive is powered down, the snubber operably manipulates the engaging surfaces to abuttingly engage each disc at points both above and below each disc in order to fixedly support the disc at the outer edge thereof. Because of the inherent uncertainty in the location of the disc edge due to mechanical tolerance stacking, a certain amount of elastic deflection is imparted to the disc. A semi-compliant material is also employed in the engaging surfaces so as to accommodate the part-to-part variation of the disc location.
The present invention provides an improved support for the edges of a plurality of discs forming a disc pack in a disc drive, thereby minimizing damage to the discs and other associated components following an external shock on the disc drive. These advantages and other features of the present invention will be apparent from the following description when read in conj

Affiliated with

Also associated with

Rating

Snubber for a disc drive does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Snubber for a disc drive, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Snubber for a disc drive will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2440540