Elastic Switch Device Vent Cavity Foreign Matter Ingress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switch devices with air vent holes are prone to ingress of foreign matter, such as dust or water droplets, which can lead to contact failures or short circuits between the movable and stationary contact plates.
Innovation Solution
A switch device with a substrate having through holes not electrically connected to the circuit, covered by an elastic sheet with dome-shaped cavities and air grooves that form nonlinear paths to deter foreign matter ingress, and a cover member with a gap smaller than the foreign matter size to prevent entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an air vent hole is provided in the shield plate to prevent air compression during switch operation, then the ease of operation is improved, but foreign matter such as dust or water droplets can ingress into the space between the movable contact plate and switch substrate, causing contact failures or short circuits
Solution Approach 1:
The air vent hole is segmented into two separate functional components: a through hole in the substrate for air passage, and an air groove in the elastic sheet that connects the cavity to the through hole. This segmentation allows air to escape during operation while the through hole remains electrically isolated from the circuit, preventing foreign matter ingress that would cause contact failures or short circuits.
Solution Approach 2:
The air groove acts as an intermediary element between the closed cavity and the through hole. It provides a controlled air passage that allows air to escape during switch pressing while maintaining electrical isolation, thus mediating between the need for air venting and the need to prevent foreign matter ingress and electrical interference.
2Device complexity
If the through hole is electrically connected to the substrate circuit, then the structure is simplified, but electrical interference or short circuits may occur when foreign matter enters
Solution Approach 1:
The through hole is designed with local quality differentiation: it provides air passage functionality while being explicitly designed NOT to be electrically connected to the substrate circuit. This localized electrical isolation at the through hole position prevents electrical interference and short circuits when foreign matter enters, while maintaining the overall structural simplicity of having a direct air passage.
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
Effectively suppresses the ingress of foreign matter, reducing the likelihood of contact failures and short circuits while allowing air to pass through, maintaining reliable switch operation.
Implementation Method 1
a contact rubber, being an elastic sheet covering the substrate, provided with a dome-shaped cavity configured to make a second contact portion including a second contact corresponding to the first contact elastically deformable to be capable of contacting to and separating from the first contact
Data Source
AI summary
A switch device includes a substrate provided with at least one first contact and including at least one through hole, and a contact rubber, being an elastic sheet covering the substrate, provided with a dome-shaped cavity configured to make a second contact portion including a second contact corresponding to the first contact elastically deformable to be capable of contacting to and separating from the first contact, a vent cavity portion provided corresponding to the through hole, and an air groove communicating with the cavity and the vent cavity portion between the substrate and the elastic sheet. The through hole is an independent through hole being not electrically connected to a circuit of the substrate.