Blind Cord Drive Position Detection Without End-Stop Torque
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Solution Overview
Problem
Existing electric drive units for blinds cause stress on cords and mechanical components due to high torque when reaching the wound up end position, leading to potential weakening of the cords over time.
Innovation Solution
An electric drive unit for blinds that uses a control circuitry to control a DC-driven electric motor based on rotation detection sensors, eliminating the need for mechanical means to define the end position, allowing for easy adjustment and reducing stress on the cords by controlling the motor's operation through detection pulses and time development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical means (abutment) are used to define the wound up end position, then the end position is precisely defined, but the cords and mechanical components experience high torque stress leading to reduced reliability
Solution Approach 1:
The patent replaces the mechanical abutment system with an electronic control system using rotation detection sensors. The control circuitry detects the number of rotations of the cord winding/unwinding unit and stops the motor electronically without requiring mechanical contact. This eliminates the high torque impact that occurs when the blind hits the mechanical abutment, thereby preserving cord strength and reliability while still achieving precise end position definition through rotational counting.
2Ease of operation
If mechanical means are used to stop the blind at the wound up end position, then the position is accurately controlled, but the cords are stressed with high torque over time
Solution Approach 1:
The patent substitutes the mechanical stopping mechanism with an electronic control approach. The control circuitry monitors the rotation of the cord winding/unwinding unit via rotation detection sensors and cuts power to the motor precisely when the desired number of rotations is achieved. This electronic stopping method maintains accurate end position control while eliminating repeated high-torque impacts on the cords, thereby improving cord durability without sacrificing operational precision.
3Measurement precision
If the blind is stopped by mechanical means at the end position, then positioning is achieved, but current increases and mechanical wear occurs
Solution Approach 1:
The patent replaces the mechanical impact-based positioning system with an electronic rotation-counting system. Rotation detection sensors detect the rotational position of the cord winding/unwinding unit, and the control circuitry stops the motor based on the detected rotation count rather than mechanical contact. This eliminates the harmful mechanical stress and current spikes associated with the blind striking the mechanical abutment, while maintaining precise position detection through electronic means.
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 enables the electric drive unit to change the wound up end position without high torque stress, prolonging the lifespan of the cords and reducing mechanical wear.
Implementation Method 1
a rotation detection sensor, which cooperates with a rotating element having at least two discrete elements, in order to detect increments of a rotation of the electric motor by the passage of the discrete elements
Data Source
AI summary
Techniques include increasing a rotation speed of an electric motor configured to wind the architectural covering over a first time period to a first rotation speed. The techniques further include responsive to the first rotation speed being reached and after the first time period, rotating the electric motor at the first rotation speed for a second time period. The techniques further include after the second time period, increasing the rotation speed of the electric motor over a third time period to a second rotation speed.