Cam-Actuated Input Switch for Rubber Dome Fatigue Reduction
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Solution Overview
Problem
The existing power window operation switch device in Japanese Patent No. 3810920 experiences localized fatigue and premature failure of the rubber sheet due to oblique deformation of the dome portion, leading to a shortened lifespan.
Innovation Solution
The input device incorporates a cam member that performs two distinct swinging movements to activate first and second switches, with actuators sliding perpendicular to the substrate, and a rubber sheet protected by a housing, ensuring straight downward deformation of dome portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pusher inclines and obliquely pushes a restoring means (dome portion) of a rubber sheet, then the switch device can be operated, but the dome portion is pushed obliquely downward and elastically deforms while twisting, causing fatigue to accumulate in a local part and shortening the lifetime of the rubber sheet
Solution Approach 1:
Instead of having the pusher directly and obliquely push the dome portion (traditional approach), the invention inverts the mechanism by using a cam member that converts rotational motion into linear motion perpendicular to the substrate. This inversion ensures the dome portion is pushed straight downward without oblique deformation, eliminating the source of fatigue while maintaining switch operability.
2Adaptability or versatility
If a cam member performs two distinct swinging movements to activate first and second switches, then the switching functionality is improved, but the device complexity increases
Solution Approach 1:
The cam member is designed to perform multiple functions: it activates both the first switch and the second switch through its swinging movements, and it also provides the restoring force to return the operation knob to its initial position. This multi-functionality reduces the need for separate restoring mechanisms and simplifies the overall device structure despite the enhanced switching functionality.
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 configuration enhances the rubber sheet's lifetime by minimizing localized stress and preventing premature failure, thereby improving the durability and reliability of the switch device.
Implementation Method 1
the dome portion is pushed obliquely downward and elastically deforms while twisting
Data Source
AI summary
An input device includes housing; operation nob; cam member swingable in a direction intersecting with pivoting direction of operation knob, and performing swinging as first movement in response to operation knob pivoting in first angular range and performing swinging as second movement succeeding first movement in response to operation knob pivoting in second angular range; substrate; first switch on substrate, switched on in conjunction with first movement of cam member; and second switch on substrate, switched on in conjunction with second movement of cam member. When operation force is ceased, operation knob is automatically restored by restoring forces from first and second switches. Input device includes: first actuator to be slid in conjunction with first movement of cam member to push first switch perpendicularly to substrate; and second actuator to be slid in conjunction with second movement of cam member to push second switch perpendicularly to substrate.