Disk Drive Head-Arm Assembly with Dynamic Axial Positioning

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Solution Overview

Problem

Conventional hard disk drives require multiple read/write heads for each disk surface, increasing cost and height due to the need for axial spacing, while also limiting volumetric efficiency and data density.

Innovation Solution

A disk drive apparatus with a movable head-arm assembly and disk separator that creates axial gaps between disks, allowing access to only two writable surfaces at a time, using shingled writing and write append formats to enhance data density and reduce the number of read/write heads needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple read/write heads are used for each disk surface, then data access capability is improved, but device height and cost increase

Engineering Contradiction:

Improvedata access capabilityVSAvoiddevice height

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The patent combines multiple read/write heads into a single shared head assembly that can access multiple disk surfaces sequentially. Instead of having dedicated heads for each surface, one head assembly serves all surfaces by moving between them, reducing the number of heads required and thereby decreasing device height and cost while maintaining data access capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic disk positioning where disks can be axially moved to bring specific surfaces into the access zone of the read/write head. This dynamic reconfiguration allows a single head to serve multiple surfaces over time, eliminating the need for static multiple heads and reducing overall device height.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If multiple read/write heads are used for each disk surface, then data access capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvedata access capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent merges the function of multiple heads into a single shared head assembly, reducing the number of components that need to be manufactured and assembled. This consolidation lowers manufacturing costs while maintaining the capability to access multiple disk surfaces through sequential positioning.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The read/write head assembly is designed as a universal component that can access any disk surface in the stack, rather than being dedicated to a single surface. This multi-functionality reduces the total number of heads needed, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If axial spacing is provided for each disk surface, then head access is enabled, but volumetric efficiency decreases

Engineering Contradiction:

Improvehead accessVSAvoidvolumetric efficiency

Core Design Contradiction:

Ease of operationVSVolume of stationary object

Solution Approach 1:

The patent uses dynamic axial positioning of disks to create access gaps only when needed. Disks are moved axially to position specific surfaces into the read/write head's access zone, eliminating the need for permanent axial spacing between all disks. This dynamic approach maximizes volumetric efficiency while maintaining head access capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system periodically creates axial gaps between disks as needed for head access, rather than maintaining continuous spacing. The disks are positioned closely together most of the time to maximize density, and gaps are created temporarily when a particular surface needs to be accessed, then closed again afterward.

Inventive Principle:

Principle #19Periodic action

4Ease of operation

If axial spacing is provided for each disk surface, then head access is enabled, but data density decreases

Engineering Contradiction:

Improvehead accessVSAvoiddata density

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent implements dynamic disk positioning that creates axial gaps only when specific surfaces need to be accessed. During normal operation, disks are positioned as closely as possible to maximize data density. When access is required, the system temporarily positions disks to create gaps, then returns to high-density configuration, thereby maintaining both head access and high data density.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8208215B2Techniques for emulating sequential device with constrained disk drive

Publication Date: 2012.06.26 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A disk drive apparatus includes at least one disk, a head-arm assembly, and a controller circuit. The head arm assembly includes at least one read/write head. The head-arm assembly is movable to enable the read/write head to access a writable surface of the disk. The controller circuit also causes the read/write head to record data on the writable surface of the disk in a write append format.