Radial Symmetry Switch Strip for Automotive Anti-Trap Detection
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Solution Overview
Problem
Existing anti-trap protection switch strips for automotive vehicles have directional installation requirements and poor detection of certain obstructions like wood or plastic, making them cumbersome and expensive to install, and inefficient in detecting obstructions across all orientations.
Innovation Solution
A radially symmetrical switch strip with a dielectric air-filled space between concentric inner and outer electrodes, featuring deformable spacers and protrusions, which allows for capacitive and tactile detection of obstructions without a preferred switching direction, enabling easy installation and improved detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional switch strip with directional electrodes is used, then the switching function works in a specific direction, but the installation becomes cumbersome and expensive due to orientation requirements
Solution Approach 1:
The patent applies asymmetry in reverse - it creates radial symmetry in the electrode arrangement. The outer electrode forms a complete circle around the inner electrode, making the switch strip functionally identical in all radial directions. This symmetry eliminates the need for specific installation orientation, allowing the switch strip to be installed in any direction while maintaining reliable switching function.
2Reliability
If tactile anti-trap protection is used, then reliable detection is achieved, but a certain compressive force is required which can be a drawback when limbs are trapped
Solution Approach 1:
The patent changes the detection parameter from purely mechanical contact to capacitive detection. By monitoring changes in capacitance between the inner and outer electrodes, the system can detect obstructions at much lower force levels. The capacitive detection threshold can be set to trigger when even minimal deformation occurs, allowing detection of trapped limbs with very small compressive forces well below what would be harmful.
3Loss of time
If capacitive anti-trap protection is used, then early detection of obstructions is achieved, but certain materials like wood or plastic are poorly detected or not detected at all
Solution Approach 1:
The patent implements a dynamic detection system that adapts its detection method based on the situation. It operates in two modes: capacitive detection for early warning when capacitance changes occur, and tactile detection when electrode contact occurs. This dynamic switching between detection modes ensures that both early detection (capacitive) and reliable material-agnostic detection (tactile) are achieved throughout the closure process.
4Ease of manufacture
If switch strips with preferred deformation direction are used, then manufacturing is simplified, but the detection capability is reduced in certain directions
Solution Approach 1:
The patent uses radial symmetry (the opposite of directional asymmetry) to create an outer electrode that is circular and evenly spaced around the inner electrode. This symmetric configuration ensures that the capacitive and tactile detection characteristics are identical in all radial directions, eliminating directional detection preferences while maintaining manufacturing simplicity through the regular geometric pattern.
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 switch strip ensures reliable detection of obstructions irrespective of orientation, reducing installation complexity and improving detection accuracy for various materials, including wood and plastic, by triggering a switching event through capacitive changes or electrode contact.
Implementation Method 1
The space between the outer electrode and the inner electrode is insulating and dielectric
Implementation Method 2
The space between the outer electrode and the inner electrode is insulating and dielectric
Implementation Method 3
The outer electrode is deformable by a force applied from the outside. The deformation of the outer electrode is able at least in portions to bring the inner electrode and the outer electrode into contact with each other
Data Source
AI summary
The invention relates to a switch strip (10) for an apparatus for detecting an obstruction (210) in the movement range (221) of a closure element (220), in particular of an automotive vehicle (200). The switch strip (10) has an inner electrode (20), an outer electrode (30) approximately concentrically surrounding the inner electrode (20) at a distance (D), and a space (40) filled with air, which is arranged between the outer electrode (30) and the inner electrode (20) and which is dielectric. Furthermore, the switch strip (10) has a spacer (50) which is deformable in a direction transverse to the longitudinal direction. The spacer (50) spaces and insulates the two electrodes (20, 30) from one another. The outer electrode (30) is deformable by a force (F) applied from the outside. The deformation of the outer electrode (30) is able to at least in portions bring the inner electrode (20) and the outer electrode (30) into contact with each other. Such a switch strip (10) is also referred to as a tactile switch strip (10).