Spring Drive System for Cordless Window Shades
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Solution Overview
Problem
Conventional cordless window shades with spring motors are complex and heavy due to multiple moving parts required to transmit spring torque, posing a strangulation risk with exposed cords and needing an improved drive system.
Innovation Solution
A simplified spring drive system comprising a housing, rotary drums, gears, spools, and springs that unwind and wind around each other to rotate the suspension cords, reducing the number of components and weight, while ensuring safe operation without exposed cords.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spring motors use multiple moving parts to transmit spring torque, then the torque transmission is reliable, but the weight and complexity of the drive system increase
Solution Approach 1:
The patent combines the spring motor assembly with the bottom rail into a single integrated unit. The spring, spool, and gear components are housed within the bottom rail structure itself, eliminating the need for separate motor housings and reducing the number of discrete parts. This merging of functions reduces overall weight while maintaining reliable torque transmission from the spring to the suspension cords.
2Reliability
If conventional spring motors use multiple moving parts to transmit spring torque, then the torque transmission is reliable, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified components. The bottom rail serves both as a structural support and as the housing for the spring motor assembly. The spool is directly connected to the suspension cord attachment point, and the gear mechanism is incorporated within the same assembly. This reduction in separate components simplifies the overall device while maintaining reliable torque transmission through the integrated mechanical linkages.
3Ease of operation
If operating cords are exposed for manual actuation, then the window shade can be easily operated, but there is a strangulation threat to children
Solution Approach 1:
The patent removes the traditional exposed operating cord from the system entirely. Instead of using a cord that extends outside the window shade mechanism for manual operation, the design incorporates a cordless operation system where the suspension cords are contained within the housing. Users can operate the shade through a remote control or other cordless interface, eliminating the strangulation hazard while preserving ease of operation through alternative control methods.
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 solution provides a lightweight, compact, and safer cordless window shade operation by directly connecting springs to rotary drums, reducing the overall weight and complexity of the drive system, enhancing user safety and ease of manual operation.
Implementation Method 1
The spring unwinds from the spool and winds around the rotary drum when the rotary drum rotates to unwind the suspension cord therefrom
Data Source
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AI summary
A spring drive system for a cordless window shade includes multiple rotary drums respectively connected with suspension cords, and one or more springs respectively connected with the rotary drums. The rotary drums are operatively connected with each other, so that they can synchronously rotate to wind and unwind the suspension cords. Moreover, each of the rotary drums is connected with an end of one spring. The spring torque can act to sustain a bottom part of the window shade at any desired height, and drive rotation of the rotary drums to wind the suspension cords when the bottom rail is raised upward.