Unequal-Torque Coil Spring for Steady Curtain Folding
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Solution Overview
Problem
Existing curtain set designs with equal-torque coil springs struggle to match the varying gravity forces of curtains at different heights, requiring additional weights and frequent torque adjustments to maintain a steady folding speed, and the methods to achieve unequal torque, such as boring holes or varying thicknesses, are prone to mechanical damage and processing difficulties.
Innovation Solution
An unequal-torque coil spring is fabricated with different curvatures in multiple sections of a reed strip, allowing for varying torque reactions to meet the requirements of the curtain-folding process, with a ratio of maximum to minimum torque between 4:1 and 1:1, and assembled in a spring motor to drive reel drums for efficient curtain folding and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an equal-torque coil spring is used in the spring motor, then the structure is simple and easy to manufacture, but the torque cannot match the varying gravity forces of curtains at different heights, requiring additional weights and frequent torque adjustments
Solution Approach 1:
The coil spring is designed with different curvatures in different sections along its length. Specifically, the spring has a first curvature in a first section and a second curvature different from the first curvature in a second section. This local variation in curvature allows different sections to provide different torque characteristics, enabling the spring to adapt to varying gravity forces at different curtain heights while maintaining a relatively simple manufacturing process.
2Adaptability or versatility
If methods such as boring holes or varying thicknesses are used to achieve unequal torque, then the torque can be adjusted to match varying gravity forces, but the spring is prone to mechanical damage and processing difficulties
Solution Approach 1:
Instead of using complex processing methods like boring holes or varying thicknesses that compromise spring integrity, the invention changes the curvature parameter along the length of the spring. The spring maintains a substantially constant cross-section and uniform material thickness, while the curvature varies from a first curvature in the first section to a second curvature in the second section. This approach achieves the desired unequal torque characteristics without introducing weak points or processing difficulties.
3Adaptability or versatility
If additional weights are added to match varying gravity forces, then the torque can be adjusted, but the device complexity increases
Solution Approach 1:
The invention integrates the torque adjustment function directly into the coil spring structure itself by varying the curvature in different sections, eliminating the need for additional weights or complex adjustment mechanisms. The spring's own geometry is modified to provide different torque characteristics at different positions, thereby achieving adaptability without increasing device complexity.
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 unequal-torque coil spring provides dynamic torque distribution to ensure smooth and steady curtain folding, preventing downward or upward momentum impacts, and simplifies the fabrication process by using distinct curvatures to achieve the necessary feedback forces at different heights.
Implementation Method 1
the spring motor 2 employs an elastic reaction force of approximately equal torque from a strip of equal-torque coil spring 20
Data Source
AI summary
An unequal-torque coil spring and a spring motor thereof which is adapted for a curtain set that can automatically fold back a curtain; the same provides a feedback torque that responds to different stages of a curtain-folding working process and generates various corresponding torque in response, as each of the different stages requires a different force. Consequently, the curtain can be folded back at a steady speed, and positionally fixed at any height when the curtain is lowered.