Capacitive Proximity Sensor and Stopper Bar for Vehicle Door Anti-Pinch
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Solution Overview
Problem
Existing anti-pinch systems primarily focus on power windows and sliding doors, leaving a gap in safety for manually operated vehicle doors, which can still cause pinching incidents, especially when children or objects interfere with the closing mechanism.
Innovation Solution
A system incorporating capacitive proximity sensors and accelerometers in each door, coupled with a stopper bar and release mechanism, which activates when an object is detected along the closing surfaces, preventing the door from fully closing to avoid pinching, utilizing a control unit to manage the stopper bar's position and a solenoid or latch for activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual vehicle doors are operated without anti-pinch technology, then the door closing operation is simple and reliable, but pinching incidents can occur when children or objects interfere with the closing mechanism
Solution Approach 1:
The system performs preliminary detection of obstacles using capacitive proximity sensors along the closing surfaces before the door completes its closing motion. When an object is detected, the control unit activates the stopper bar in advance to prevent the door from closing entirely, thereby avoiding pinching incidents while maintaining normal door operation
Solution Approach 2:
The stopper bar acts as an intermediary mechanical element between the door and the obstacle. When activated by the control unit, the stopper bar physically blocks the door from closing further, serving as a mediator that prevents direct contact between the door and any detected objects, thus eliminating the pinching hazard
2Object-affected harmful factors
If capacitive proximity sensors and accelerometers are added to detect objects during door closure, then pinching safety is improved, but device complexity increases
Solution Approach 1:
The capacitive proximity sensors serve multiple functions: they detect objects along the closing surfaces, determine the position of the stopper bar, and provide data to the control unit for deciding when to activate the stopper bar. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while maintaining comprehensive safety coverage
Solution Approach 2:
The system replaces traditional mechanical contact-based detection with capacitive proximity sensors that can detect objects without physical contact. This substitution eliminates the need for complex mechanical switches or contact sensors, simplifying the overall system while improving reliability and safety response
3Loss of time
If the stopper bar is activated immediately upon object detection, then safety response time is reduced, but false activation may occur due to residual acceleration forces
Solution Approach 1:
The control unit continuously monitors acceleration data from the accelerometer during door closure. It uses this feedback to distinguish between normal closing acceleration and the specific acceleration pattern that occurs when the stopper bar is activated. The system waits for acceleration to return to baseline levels before confirming object detection and activating the stopper bar, thereby preventing false activation while maintaining rapid safety response
Solution Approach 2:
The system dynamically adjusts its detection criteria based on the real-time acceleration state of the door. Instead of using a fixed threshold, the control unit analyzes the acceleration profile and only triggers the stopper bar when the door has stopped accelerating, indicating a stable state. This dynamic approach ensures reliable detection while avoiding false positives during transient acceleration phases
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 prevents manual vehicle doors from pinching by accurately detecting objects or hands during closure, ensuring safety by stopping the door from fully closing when obstacles are present, thus protecting both the door and the object.
Implementation Method 1
measuring a capacitance of a field extending through the aperture of said door using the capacitive proximity sensor
Implementation Method 2
monitoring a signal from the accelerometer, the stopper bar being activated if the door after accelerating stops accelerating
Implementation Method 3
the stopper bar being held in the non-triggered position by a solenoid
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A system for avoiding pinching in vehicle doors (1) comprises capacitive proximity sensors (2) for being mounted at each door (1) along the closing surfaces. It further comprises an accelerometer (6) for being arranged in each door (1), a stopper bar (3), and a release mechanism (4) for the stopper bar (3). The capacitive proximity sensors (2), the accelerometer (6), and the release mechanism (4) are connected to a control unit (7) arranged such that the stopper bar (3) is moved to a blocking position when the capacitive proximity sensor (2) for the same door senses an object and the door (1) has stopped accelerating.