Window Sash Drive With Absolute Position Sensing After Power Loss
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Solution Overview
Problem
Conventional door position detection systems in automatic revolving doors lose position data during power outages, requiring time-consuming learning cycles, and absolute encoders are expensive and require significant installation space.
Innovation Solution
A drive system with a sensor wheel directly coupled to the output wheel, allowing precise absolute position detection with minimal installation space and cost, utilizing a sensor wheel circumference that matches the output wheel's circular arc movement, and a Hall sensor for detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional relative encoders are used for door position detection, then the device complexity is low and manufacturing cost is reduced, but the system loses position data during power outages requiring time-consuming recalibration
Solution Approach 1:
The patent applies preliminary action by pre-mapping the entire door position range to the sensor wheel's rotation range before operation. The sensor wheel is dimensioned and positioned such that its circumference corresponds to the full opening/closing arc, allowing the system to directly read absolute position without needing post-power-loss recalibration. This pre-configured mapping enables immediate position recovery after power outages.
2Reliability
If absolute encoders are used for door position detection, then position data is retained during power outages, but the device complexity increases and installation space requirements increase
Solution Approach 1:
The patent extracts only the essential function of absolute encoders (position detection) while removing their complex internal structures. Instead of using a complete absolute encoder with multiple sensors and gears, the invention uses a simplified sensor wheel with a single sensor that reads position directly from the output shaft's rotation, achieving absolute position detection with minimal complexity.
Solution Approach 2:
The patent replaces expensive absolute encoders with a cost-effective alternative using simple components: a sensor wheel, single sensor, and basic coupling mechanism. This substitution achieves the same functional result (absolute position retention) at lower cost and complexity, effectively using simpler, cheaper components to replace complex expensive ones.
3Reliability
If absolute encoders are used for door position detection, then position data is retained during power outages, but the installation space requirements increase
Solution Approach 1:
The patent applies nesting by integrating the sensor wheel within the existing output shaft assembly. The sensor wheel is mounted on the output shaft itself, utilizing the same rotational space, and the sensor is positioned within the existing housing structure. This nested arrangement allows absolute position detection without requiring additional installation space outside the original encoder mounting location.
4Ease of manufacture
If a sensor wheel is coupled to the output wheel for position detection, then the manufacturing cost is reduced, but the measurement precision may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the sensor wheel's dimensional parameters - specifically its diameter and circumference - to precisely match the output shaft's rotational parameters. The sensor wheel is designed with a circumference that corresponds exactly to the full door opening/closing arc, and the sensor reading positions are calibrated to provide accurate position mapping throughout the entire range of motion, maintaining high measurement precision.
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
Enables precise door position detection without the need for post-power outage recalibration, using a compact and cost-effective design that can be easily retrofitted, ensuring reliable operation and safety.
Implementation Method 1
a sensor for detecting a rotational movement of the at least one sensor wheel
Data Source
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AI summary
The present invention relates to a drive for a sash of a window, door, or the like, comprising a housing, a motor, a gear unit housed in the housing for driving an output shaft for opening and/or closing the sash, wherein the output shaft is rotationally fixed to an output gear of the gear unit, and a sensor unit for detecting the position of the output gear, wherein the sensor unit has at least one sensor wheel which is effectively coupled to the output gear, and a sensor for detecting a rotational movement of the at least one sensor wheel. The circumference of the at least one sensor wheel corresponds essentially to the length of a circular arc of the output gear, which the output gear traces when the sash moves from the open position to the closed position and/or vice versa.