Cordless Roller Blind Spring-Brake Self-Locking Without Torque Damage
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Solution Overview
Problem
Existing roller blinds, both mechanical and power-driven, face issues such as bead chain breakage, clutch damage due to torque, and aesthetic and safety concerns from cords, which can entangle and cause injuries.
Innovation Solution
A cordless roller blind design featuring a roller tube with a coil spring and a brake device that balances torsion force, friction, and weight to allow manual raising and lowering without external force, self-locking at desired positions, and adjustable friction to accommodate different blind fabrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bead chain is used to wind and self-lock the roller tube, then the blind fabric can be fixed in place, but the bead chain breaks due to excessive pulling force and the clutch is damaged by torque
Solution Approach 1:
The invention removes the bead chain from the system entirely, replacing it with a cordless design that uses a spring-loaded winding mechanism with a brake device for self-locking, thereby eliminating the component that breaks under excessive force
Solution Approach 2:
The invention introduces a dynamic brake device that can adjust friction force to match the torque of the spring, allowing the system to self-lock at any position without excessive force being transmitted to the roller tube or internal components
2Object-affected harmful factors
If the roller blind is power-driven by a motor, then cord safety issues are resolved, but the motor shaft is subjected to full torque from the blind fabric weight causing load on the motor
Solution Approach 1:
The invention uses a spring mechanism that provides a counterbalancing force to the weight of the blind fabric, so the motor or manual operation only needs to overcome the difference between the spring torque and fabric weight, rather than the full weight torque
Solution Approach 2:
The spring-loaded mechanism with brake device enables self-service winding and self-locking functionality, reducing the power requirement by allowing the spring to do most of the work of lifting the fabric while the brake maintains position
3Reliability
If the coil spring torque and brake friction are balanced to enable self-locking, then the blind fabric remains stationary without external force, but the roller tube and limit component are subjected to excessive torque during self-locking
Solution Approach 1:
The brake device is designed to dynamically adjust its friction force to match the spring torque at any position, allowing self-locking without transmitting excessive torque to the roller tube or limit components
Solution Approach 2:
The brake device acts as an intermediary between the spring and the roller tube, absorbing the torque balance through friction and preventing excessive torque from being transmitted to the roller tube and limit components
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
Prevents irreversible damage by distributing torque evenly, ensures safe operation without cords, and allows for easy adjustment of friction to meet various fabric weights, enabling reliable and safe operation.
Implementation Method 1
A coil spring is arranged in the roller tube, and a torsion force of the coil spring changes as the roller tube rotates
Implementation Method 2
friction provided by the brake device and a weight of a hanging portion of the blind fabric balance at equilibrium
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A cordless roller blind includes a roller tube (1), a blind fabric (2) wound around the roller tube (1), and at least one brake device (4). A coil spring (23) is arranged in the roller tube (1), and the torsion of the coil spring (23) changes as the roller tube (1) rotates. The torsion force of the coil spring (23), the friction force provided by the brake device (4) and the weight of a hanging portion of the blind fabric (2) are mutually balanced, so that the blind fabric (2) remains stationary at any position without an external force. In the provided cordless roller blind, the blind fabric (2) can be manually raised or lowered as required in use and self-locked in the desired position, and the roller tube (1) itself and a limiting component are not subjected to excessive torque during the self-locking process to avoid irreversible damage.