Thin Sheet Spring Keyboard Button for Consistent Click Force
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Solution Overview
Problem
Previous information handling systems with plastic button holders faced issues such as varying bending forces required for activation and misalignment due to deformation during injection molding, affecting the size and functionality of buttons.
Innovation Solution
A button mechanism utilizing a thin sheet spring that exerts tension to bias the button towards a normal position, allowing it to snap back and activate a contact dome upon force application, providing a consistent click ratio and reducing the need for plastic arms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic button holders are used, then buttons can be manufactured with injection molding, but varying bending forces and misalignment due to deformation occur
Solution Approach 1:
The patent changes the material parameter from plastic to thin sheet metal, which fundamentally alters the mechanical properties. The thin sheet metal spring provides consistent elastic deformation characteristics that are not affected by injection molding processes, thereby eliminating the misalignment issues while maintaining manufacturability through sheet metal forming techniques
Solution Approach 2:
The thin sheet metal spring is designed as a simple, inexpensive component that can be easily manufactured and replaced if needed. The simplicity of the thin sheet design allows for cost-effective production through standard sheet metal forming processes, making it a practical alternative to complex plastic injection molded parts
2Force
If plastic arms are used in button holders, then buttons can be biased to normal position, but the size of plastic holders increases
Solution Approach 1:
The patent employs a thin sheet metal spring that functions as a flexible element to provide the necessary biasing force. This thin film approach eliminates the need for bulky plastic arms, as the spring's elastic properties allow it to generate sufficient restoring force within a minimal space, thereby reducing the overall holder size
Solution Approach 2:
The button holder is segmented into distinct functional components: the thin sheet metal spring for biasing, the contact dome for signal activation, and the button cap for user interaction. This segmentation allows each component to be optimized independently, with the spring providing force without requiring large structural support elements
3Reliability
If thin sheet spring is used, then consistent activation force and higher click ratio are achieved, but manufacturing complexity increases
Solution Approach 1:
The thin sheet metal spring is designed to be self-functional, providing both the biasing force and the click feedback mechanism through its own elastic deformation. The spring's natural rebound characteristic automatically provides the click sensation to the user without requiring additional components, thereby maintaining simplicity while achieving reliable consistent activation force
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
The thin sheet spring mechanism ensures a consistent activation force and higher click ratio compared to previous designs, while minimizing the size and potential misalignment issues, enhancing the usability and reliability of buttons in information handling systems.
Implementation Method 1
The thin sheet spring may exert a tension force on the button and the module to bias the button toward a normal position. In response to the force being removed from the button, the tension force may cause the thin sheet to snap back to an original position
Data Source
AI summary
A button mechanism includes a button, a module, and a thin sheet spring. The thin sheet spring is in physical communication with the button and with the module. The thin sheet spring exerts a tension force on the button and the module to bias the button toward a normal position. In response to a force greater than the tension force being exerted on the button, a portion of the thin sheet stretches to enable the button to be placed in a contact position. In response to the force being removed from the button, the tension force causes the thin sheet to snap back to an original position and biases the button toward the normal position.