Capacitive Switch Assembly Using Hose Pressure Sensing Redundancy
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Solution Overview
Problem
Existing capacitive switching devices are costly and labor-intensive to produce and assemble, with a high risk of failure due to sensor inaccuracies and environmental influences, leading to unreliable switching signals.
Innovation Solution
A flexible hose with hollow chambers and pressure sensors is used between the cover plate and housing, allowing for reliable detection of pressure changes and generation of redundant switching signals, ensuring accurate actuation and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are positioned between the cover plate and housing to detect capacitance changes, then switching reliability is improved, but manufacturing cost and assembly complexity increase significantly
Solution Approach 1:
The patent replaces the complex capacitive sensor system with a simple pressure sensor connected to a hollow chamber. When the cover plate moves, it compresses the hollow chamber, creating pressure changes that are easily detected by the pressure sensor. This mechanical pressure-based approach substitutes the complex electrical field-based capacitive sensing, dramatically simplifying assembly while maintaining reliability.
Solution Approach 2:
The patent extracts the sensing function from the complex capacitive sensor assembly and isolates it into a separate pressure detection system. The hollow chamber acts as an intermediary that converts cover plate movement into pressure changes, which are then detected by a simple pressure sensor. This separation simplifies the overall system architecture and reduces assembly complexity.
2Reliability
If multiple sensors are used around the switching housing to ensure redundancy, then switching reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple sensing functions into a single pressure sensor system. Instead of using multiple capacitive sensors around the housing, a single pressure sensor connected to a hollow chamber can detect cover plate movement in any direction. This consolidation reduces the number of components and significantly lowers manufacturing costs while maintaining redundant detection capability.
Solution Approach 2:
The hollow chamber serves multiple functions: it transmits mechanical movement from the cover plate to the pressure sensor, provides structural support, and enables detection of actuation force in various directions. This multi-functional design replaces what would otherwise require multiple specialized sensors, reducing overall system cost.
3Ease of operation
If capacitive sensors are used to detect button actuation, then switching function is achieved, but susceptibility to environmental influences and sensor failure increases
Solution Approach 1:
The patent uses pneumatic pressure detection instead of electrical capacitive sensing. The hollow chamber fills with air (or another gas), and cover plate movement compresses the gas, creating pressure changes detected by the pressure sensor. This pneumatic approach is inherently more robust against environmental factors like humidity, temperature variations, and electromagnetic interference that affect capacitive sensors.
Solution Approach 2:
The pressure sensor and hollow chamber assembly provides a simpler, more durable alternative to complex capacitive sensor arrays. The mechanical pressure-based system is less susceptible to degradation from environmental factors and sensor drift, providing long-term reliability without requiring expensive precision components.
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 solution provides a cost-effective and reliable method for detecting cover plate movement and generating redundant switching signals, enhancing the reliability and redundancy of the switching device while minimizing assembly complexity and environmental interference.
Implementation Method 1
the respective pressure sensor detects the pressure fluctuations of the medium in the respective hollow chamber and transmits these to the evaluation unit for the physical calculation of the pressure state inside the hose
Data Source
Figure 2a~2b
AI summary
In a capacitive switching device (1) for converting a manual or mechanical actuation movement (2) into an electrical switching signal by which an electrical device is controlled, comprising: - a housing (4) in which a receiving opening (5) is incorporated, - a touchscreen (6) arranged in the receiving opening (5) of the housing (4), which is enclosed externally by an electrically insulating cover plate (7) and internally by a display (8), - wherein the cover plate (7), the touchscreen (6) and the display (8) form a unit (9) which is axially movably mounted in the receiving opening (5) of the housing (4), - wherein the touchscreen (6) and the display (8) have at least one capacitively operated button (10) which is switched when a human finger or a mechanical actuation element approaches it, - and an evaluation unit (12) electrically coupled to the respective button (10),By generating a switching signal corresponding to the respective button (10) when the electric field (23) changes, the assembly and manufacture of the components required for the switching device (1) should be cost-effective and time-saving, while simultaneously providing a permanent and reliable switching test function. This is achieved by: - inserting an elastically deformable hose (11) between the cover plate (7) and the housing (4), which encloses at least one hollow chamber (13); - providing a medium (14) in the hollow chamber (13) of the hose (11); - incorporating at least one opening (15) into the hose (11) into which a pressure sensor (16) is inserted, or by arranging one of the pressure sensors (16) in each hollow chamber (13) such thatthat the respective pressure sensor (16) detects the pressure fluctuations of the medium (14) in the respective hollow chamber (13) and forwards these to the evaluation unit (12) for the physical calculation of the pressure state inside the hose (11).