Compound spring bar
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Solution Overview
Problem
Existing non-pull roller blinds with torsion spring systems face issues with large force differences between rolling up and fully unfolding, leading to potential deformation and damage due to rapid spring expansion and inadequate force release.
Innovation Solution
A compound spring bar with a multi-spring structure, where a larger diameter spring is nested outside a smaller diameter spring, reducing the overall length and friction resistance, allowing for smoother force distribution and quicker extension force release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a constant force spring system with a torsion spring rod is used, then the roller blinds can generate sufficient torsion force, but the spring length becomes too long and mismatches curtains with smaller widths
Solution Approach 1:
The patent applies the nesting principle by placing one spring inside another spring to form a compound spring structure. The inner spring is positioned within the outer spring, allowing both springs to work together in a compact configuration. This nested arrangement reduces the overall length of the spring system while maintaining the required torsion force, thereby resolving the contradiction between sufficient force generation and excessive spring length.
Solution Approach 2:
The patent merges two separate spring systems into a single compound spring structure. By combining the outer spring and inner spring into one integrated system that works together, the patent achieves the desired torsion force with a shorter overall length compared to using a single long spring. This merging of spring functions resolves the technical contradiction.
2Force
If a torsion spring rod system is used, then the roller blinds can function properly, but the torsion force difference between rolled up and fully unfolded states is large, requiring increased counterweight
Solution Approach 1:
The nested compound spring structure allows for a more gradual distribution of torsion force during the rolling process. As the inner and outer springs unwind in sequence, the force difference between rolled up and fully unfolded states is reduced, eliminating the need for increased counterweight and simplifying the overall device.
Solution Approach 2:
The patent changes the physical parameters of the spring system by using two springs with different diameter ratios (0.3-0.7) and different wire diameters. This parameter optimization allows the compound spring to maintain more consistent torsion force throughout the rolling process, reducing the force difference that would otherwise require additional counterweight.
3Speed
If the spring expands rapidly when the curtain is pulled down quickly, then the curtain can be lowered quickly, but the structure cannot release the extension force quickly, causing deformation and damage
Solution Approach 1:
The nested compound spring structure enables rapid and controlled release of extension force when the curtain is pulled down quickly. The inner and outer springs can unwind in a coordinated manner, dissipating the extension force more effectively and preventing the deformation and damage that occurs with single-spring systems.
Solution Approach 2:
The compound spring structure provides built-in cushioning capacity through its dual-spring design. When rapid extension occurs, the nested springs can absorb and distribute the shock load, preventing sudden deformation and damage to the spring structure, thereby maintaining reliability during high-speed operation.
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 compound spring bar effectively reduces the force difference between curtain positions, prolongs the spring's service life by minimizing deformation risk, and saves space and material costs.
Implementation Method 1
During the extension, the adapter slides along the support tube or the connecting rod, with a small frictional resistance
Implementation Method 2
The non-pull roller blinds are mainly made with a torsion spring rod system. A cloth tube drives the spring to twist to generate a torsion force
Implementation Method 3
When the curtain is pulled down quickly, the spring of a spring bar expands rapidly
Data Source
AI summary
A compound spring bar includes a compound spring having one end fixed and the other end rotating as a curtain fabric opens and closes, where the compound spring includes at least two springs with different diameters, the springs are nested in layers according to their diameters, adjacent springs are connected in series, and all the springs form a combined spring; and free ends of an innermost spring and an outermost spring in the combined spring, which are not connected to other springs in series, are two ends of the combined spring. The