Magnetic Push Button Preload for Consistent Dome Switch Tactility
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Solution Overview
Problem
Conventional push button designs in computing devices face issues such as rattling, inconsistent tactile feedback, high manufacturing costs, complex assembly, and susceptibility to failure due to mechanical tolerances and adjustable preload mechanisms.
Innovation Solution
A magnetically preloaded push button design utilizing a ferromagnetic key retainer and preload magnet to consistently preload dome switches, eliminating the need for adjustable mechanisms and reducing mechanical gaps, thereby providing consistent tactile feedback and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional push button designs are used with mechanical preload mechanisms, then the dome switch can be preloaded to eliminate gaps, but the device complexity and manufacturing cost increase due to adjustable mechanisms
Solution Approach 1:
The patent replaces mechanical preload adjustment mechanisms with a magnetic field-based preload system. A magnet mounted on the dome switch bracket exerts magnetic force on the button post to provide consistent preload without requiring mechanical adjustment mechanisms, thereby reducing device complexity while maintaining reliable tactile feedback.
Solution Approach 2:
The patent changes the physical state of the preload mechanism from mechanical (adjustable screws, springs) to magnetic (field-based force). By utilizing magnetic field strength as the controlling parameter instead of mechanical displacement, the system achieves consistent preload with simpler components.
2Manufacturing precision
If conventional push button designs with mechanical preload are used, then the gap can be taken up, but manufacturing cost and assembly difficulty increase
Solution Approach 1:
The magnetic preload system eliminates the need for complex mechanical assembly steps required for traditional preload mechanisms. The magnet is simply mounted on the dome switch bracket, and the magnetic force automatically takes up gaps without requiring precision mechanical adjustment during assembly.
3Manufacturing precision
If adjustable preload mechanisms are used to accommodate mechanical tolerances, then the push button can be preloaded consistently, but the device complexity increases
Solution Approach 1:
The patent transitions from mechanical parameter adjustment (screw displacement, spring compression) to magnetic field parameter control. The magnetic field strength naturally accommodates tolerance variations in button post position and dome switch location, providing consistent preload without complex adjustment mechanisms.
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 design achieves improved tactility, reduced key rattle, consistent switch feedback, simplified assembly, and cost reduction by using a magnetically preloaded push button with ferromagnetic components and preload magnets, enhancing manufacturing efficiency and durability.
Implementation Method 1
a preload magnet that biases the button post against the dome switch by magnetic force with the ferromagnetic button cap
Implementation Method 2
a ferromagnetic key retainer attached to a distal end of the retainer post that limits travel of the button cap out of the device chassis
Data Source
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AI summary
Push buttons utilizing dome switches are often preloaded to take up any tolerances in the push button design causing a gap and provide consistent tactile feedback to a user. However, conventional push button preload techniques can be costly and difficult to consistently reproduce during push button manufacturing. The presently disclosed technology employs a new pre-load design without requiring pre-depression of the dome switch to close the gap, which permits a more forgiving tolerance to manufacturing variations.