Cordless Roller Blind Torque Matching With a Torsion Spring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing corded blinds suffer from structural imbalance, potential breakage at the joint between the screen and cord, and safety hazards due to the cord, making operation complicated and unsafe, especially for children.
Innovation Solution
A cordless blind apparatus utilizing a torsion spring mechanism where the increasing ratios of torque applied by the screen and the torsion spring to the roller are matched through a correlation equation, with a weight offsetting torque differences, ensuring balanced operation without a cord.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cord is used to rotate the rolled part of the screen, then the screen can be opened and closed, but the external force is concentrated on the cord's connecting side causing structural imbalance and potential breakage
Solution Approach 1:
The harmful cord is extracted and removed from the system. The patent replaces the cord-based operation with a direct manual operation on the roller, eliminating the cord's connecting joint that was prone to breakage and structural imbalance.
Solution Approach 2:
The roller is designed to be directly operable by hand without requiring a cord. The user can directly rotate the roller with their hand to open or close the screen, making the system self-sufficient and eliminating the need for a cord connection.
2Ease of operation
If a long cord is used for screen operation, then the screen can be controlled, but it creates safety hazards as people, particularly children, can easily trip on it
Solution Approach 1:
The harmful cord is extracted and removed from the system. The patent replaces the cord-based operation with a direct manual operation on the roller, eliminating the cord that caused tripping hazards.
Solution Approach 2:
The patent converts the harmful presence of the cord into a beneficial cordless design. By removing the cord entirely and enabling direct roller operation, the design eliminates the tripping hazard while maintaining operational functionality.
3Ease of operation
If a cord is used to operate the screen, then the screen can be rotated, but it is difficult to uniformly rotate the entire rolled part of the screen so the rotary structure is unnecessarily complicated
Solution Approach 1:
The cord that caused uneven rotation is extracted and removed. The direct manual operation on the roller ensures uniform rotation without the complications of cord-based actuation.
Solution Approach 2:
The roller is designed to rotate uniformly when directly operated by hand. The user's hand naturally applies force along the roller's circumference, ensuring even rotation without requiring complex rotary mechanisms to compensate for cord-related unevenness.
4Reliability
If the torque applied by the screen and torsion spring are not balanced, then the apparatus can be simpler, but the operation becomes unbalanced and unreliable
Solution Approach 1:
The patent employs a torsion spring with specifically adjusted parameters (wire diameter, coil diameter, number of turns, material properties) to match the torque characteristics of the screen. By carefully selecting and adjusting these parameters, the torque increasing ratios are made equal, achieving balanced operation without complex additional mechanisms.
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 apparatus achieves stable, precise, and convenient operation of the screen, maintaining balance regardless of material or diameter changes, eliminating safety hazards and structural imbalances.
Implementation Method 1
a torsion spring contracting or stretching by rotating with the roller
Implementation Method 2
a weight connected to the lower end of the screen and offsetting the difference between the magnitude of the torque applied to the roller by the torsion spring and the magnitude of torque applied to the roller by the screen
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention provides a cordless blind apparatus and a method of adjusting the balance of a cordless blind apparatus. The cordless blind apparatus includes a roller, a screen wound or unwound on the roller, and a torsion spring contracting or stretching by rotating with the roller, in which an increasing ratio of torque applied to the roller by the screen and an increasing ratio of torque applied to the roller by the torsion spring are matched to each other through the correlation equation satisfied by parameters as the wire diameter 'd' of the torsion spring, the Young's modulus 'E' of the torsion spring, the diameter 'D' of the torsion spring, the winding number 'N' of the torsion spring, the density 'ρ' of the screen, the thickness 't' of the screen, the width 'S' of the screen, the radius 'R' of the roller, and gravitational acceleration 'g'.