Window Blind Coil Spring Hub Mounting to Reduce Wear
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Solution Overview
Problem
Conventional window blind devices have a relatively short service life due to wear of the take-up drum caused by friction with the metal coil spring.
Innovation Solution
A window blind device design that eliminates the take-up drum by using a coil spring with a looped end portion sleeved on a first wheel hub, allowing the spring body to wind on a second wheel hub, reducing friction and wear, and incorporating control wheels and cord spools made of different materials to minimize noise and facilitate easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal coil spring is used in the conventional window blind, then the spring provides necessary mechanical biasing force, but friction between the coil spring and take-up drum causes wear and reduces service life
Solution Approach 1:
The patent removes the take-up drum component entirely and replaces it with a coil spring assembly that directly mounts to the drive drum. This extraction eliminates the friction interface between the coil spring and take-up drum, preventing wear while maintaining the necessary mechanical biasing force through the coil spring's elastic properties
Solution Approach 2:
The patent merges the take-up drum and drive drum into a single integrated assembly where the coil spring directly connects to the drive drum. This consolidation eliminates the separate take-up drum component and removes the harmful friction interface, while preserving the mechanical function through the coil spring's elastic deformation
2Object-generated harmful factors
If control wheels and cord spools are made of different materials, then noise is reduced and assembly is facilitated, but manufacturing complexity increases
Solution Approach 1:
The patent applies different material properties to different components (control wheels vs. cord spools) based on their specific functional requirements. Control wheels use materials optimized for low noise and user interaction, while cord spools use materials optimized for cord winding and release, creating local optimization without requiring complete material differentiation throughout the system
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 design extends the service life of the window blind by reducing friction and wear, while also reducing noise and simplifying assembly, thereby enhancing operational efficiency and durability.
Implementation Method 1
The coil spring has a looped end portion sleeved on the first wheel hub, and a spring body wound on the first wheel hub and extending from the looped end portion to terminate at a leading spring end which is connected to the second wheel hub
Data Source
AI summary
A window blind device includes a headrail, a bottomrail, a window shade, first and second control wheels, first and second cord spools, first and second cords, and a coil spring. The coil spring has a looped end portion sleeved on a first wheel hub of the first control wheel, and a spring body wound on the first wheel hub and extending from the looped end portion to terminate at a leading spring end which is connected to a second wheel hub of the second control wheel.