Curtain Bead Chain Wheel Release for Overload Safety
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Solution Overview
Problem
Conventional curtain controllers pose a risk of asphyxia due to the high strength and toughness of their bead chains, which can entangle and trap a child's or user's neck, preventing release.
Innovation Solution
A safety device for curtain controllers that automatically drops the bead chain wheel when overloaded, featuring a tapered sleeve and cone-shaped interfaces to release the bead chain wheel laterally, preventing neck entanglement and ensuring user safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bead chain is made with high strength and toughness to ensure durability, then the curtain controller can withstand repeated pulling and loading, but the bead chain can entangle and trap a child's or user's neck, preventing release and causing asphyxia
Solution Approach 1:
The patent extracts the dangerous bead chain wheel from the system when overload occurs. The tapered interface between the shaft sleeve and bead chain wheel allows automatic extraction of the wheel from the shaft sleeve when excessive force is applied, removing the hazard source while maintaining normal operation under safe loading conditions
Solution Approach 2:
The patent changes the mechanical parameter relationship between the shaft sleeve and bead chain wheel from a fixed rigid connection to a tapered frictional connection. The tapered interface allows the connection strength to vary dynamically - maintaining strong coupling under normal operation but allowing automatic disengagement when the friction threshold is exceeded due to overload
2Reliability
If the bead chain wheel is securely fixed to the shaft to prevent detachment during normal operation, then the curtain controller functions reliably, but the bead chain wheel cannot be automatically dropped when overloaded to prevent child safety hazards
Solution Approach 1:
The patent transforms the static fixed connection between shaft sleeve and bead chain wheel into a dynamic connection. The tapered interface creates a friction-based coupling that automatically adjusts its grip - maintaining secure fixation during normal operation but enabling automatic release when the friction force is overcome by excessive load, thus providing both reliability and safety
3Ease of manufacture
If conventional fixed connection methods are used between the shaft sleeve and bead chain wheel, then the structure is simple and easy to manufacture, but the bead chain wheel cannot be automatically dropped when excessive force is applied
Solution Approach 1:
The patent uses a tapered (conical) interface between the shaft sleeve and bead chain wheel instead of a cylindrical fixed connection. This curved geometric relationship creates a friction-based coupling that is simple to manufacture yet provides automatic release capability when overload occurs, eliminating the need for complex safety mechanisms while maintaining ease of assembly
Data Source
AI summary
A safety device for a curtain controller is provided. The safety device comprises a base, a bead chain wheel, and a cover. A shaft sleeve having a conical shape is disposed in a through hole of the base to connect a shaft's terminal and thus be fixed in a sleeving hole, having a shape to fit the shaft sleeve, of the bead chain wheel, so that the motions of the shaft sleeve and the bead chain wheel are linked. A bead chain is wound on the bead chain wheel. When the bead chain is pulled down, the shaft sleeve can drive the rotation of the bead chain wheel. The upper part of the cover is pivotally connected to the base, and the lower part of the cover buckles the base. Therefore, when the bead chain is instantly pulled down, the cover can be opened to drop the bead chain wheel.