Shape Memory Wire Keyboard Actuation for Height Reduction
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Solution Overview
Problem
Portable information handling systems face challenges in minimizing height while integrating keyboards, as physically-moving keys add vertical height and mechanical actuators wear out with repeated use.
Innovation Solution
The system uses shape memory wire actuated by current to rapidly and reliably retract and extend keyboard keys, maintaining minimal height with a bistable mechanism and magnetic locking, managed by a keyboard controller to monitor and apply current for efficient key behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanically-actuated keys are used to provide physical feedback, then user experience is improved, but vertical height increases and mechanical wear occurs
Solution Approach 1:
The patent replaces the traditional mechanical actuator system with an electromechanical system. A motor assembly with a drive shaft, gear mechanism, and rack-and-pinion arrangement converts rotational motor motion into linear actuator movement. This electromechanical substitution allows for more precise control, reduced wear compared to purely mechanical systems, and the ability to integrate sensing feedback to predict and manage key retraction timing.
Solution Approach 2:
The system uses a sensor to detect when the lid is approaching the closed position and triggers key retraction before the lid actually closes. This preliminary action prevents the lid from contacting the keys, avoiding mechanical impact and potential damage. The predictive timing ensures keys are retracted in advance based on detected lid position and closing speed.
2Length of moving object
If key retraction mechanism is added to reduce height, then system height is minimized, but device complexity increases
Solution Approach 1:
The motor assembly integrates multiple functions into a single compact unit: the motor provides actuation force, the drive shaft transmits motion, the gear mechanism provides mechanical advantage and direction change, and the rack-and-pinion arrangement converts rotational to linear motion. This merging of components reduces the overall space required compared to separate mechanisms and simplifies the structural design.
Solution Approach 2:
The patent moves the key retraction mechanism from a vertical compression approach to a horizontal actuation approach. Instead of compressing keys vertically to reduce height, the motor assembly actuates horizontally to pull keys inward, then uses a linkage system to convert this horizontal motion into vertical retraction. This dimensional change allows for a more space-efficient mechanism.
3Length of moving object
If mechanical actuator is used for key retraction, then height is reduced, but reliability decreases due to wear
Solution Approach 1:
The patent replaces wear-prone purely mechanical components with an electromechanical system that includes a motor, sensors, and controlled actuation. The motor provides consistent force without the sliding friction and wear of mechanical linkages. The sensor-based control system predicts when retraction is needed and executes it precisely, avoiding forced movements that would cause wear. This electromechanical substitution significantly improves reliability while maintaining the height reduction benefit.
Solution Approach 2:
The system incorporates a sensor that detects lid position and closing speed, providing feedback to the control system. This feedback enables predictive key retraction timing, ensuring keys are retracted at the optimal moment before lid contact. The feedback mechanism prevents premature or delayed retraction that would subject the actuator to unnecessary stress and wear, thereby extending the system's reliable operational life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for efficient and repeatable key retraction and extension, reducing system height and wear on actuator wires, providing a robust and user-friendly experience by minimizing unnecessary actuations and ensuring precise key implementation.
Implementation Method 1
The system uses shape memory wire actuated by current to rapidly and reliably retract and extend keyboard keys
Implementation Method 2
maintaining minimal height with a bistable mechanism and magnetic locking
Data Source
AI summary
An information handling system integrated keyboard selectively retracts and extends keys based upon detected conditions, such as housing configuration, housing motion and end user indications. Extension and retraction shuttle plates motivated by actuator wires moves a sliding plate to extended and retracted positions that define the key positions. Nickel titanium alloy actuator wires shorten upon application of current to pull the shuttle plates to the extended or retracted positions that are maintained by a lock. Limit switches remove current at detection of a desired shuttle plate position. One or more controllers manage actuator wire operation based upon detected conditions and actuator wire temperature and electrical characteristics.