Top-Down Bottom-Up Window Covering Cord Tension Mechanism

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Solution Overview

Problem

Conventional top-down bottom-up window coverings face issues with cords becoming loose and exposed when the bottom rail moves upward, affecting aesthetics and safety.

Innovation Solution

Incorporating a pre-stress unit and one-way clutch mechanism at the headrail to ensure cords between the headrail and middle rail remain organized, using a spring or sleeve to provide driving force for the first rotating shaft to receive cords when the middle rail is pushed upward.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the bottom rail moves upward to retract the covering structure, then the covered area is reduced, but the cords between the headrail and middle rail become loose and exposed

Engineering Contradiction:

Improvecovered areaVSAvoidcord arrangement

Core Design Contradiction:

Area of moving objectVSShape

Solution Approach 1:

The one-way clutch is pre-configured to automatically engage when the middle rail moves upward, triggering the first rotating shaft to rotate and wind up the cords before they can become loose or exposed, thus maintaining cord arrangement throughout the retraction process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the upward movement of the middle rail as feedback to automatically activate the cord-winding mechanism through the one-way clutch, ensuring cords are continuously managed during bottom rail retraction without manual intervention

Inventive Principle:

Principle #23Feedback

2Ease of operation

If the bottom rail continues moving upward after reaching the middle rail position, then the middle rail is pushed upward, but the cords become compressed and loose

Engineering Contradiction:

Improverail movementVSAvoidcord tension

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The one-way clutch acts as an intermediary mechanism that translates the upward push force on the middle rail into rotational motion of the first rotating shaft, which then winds up the compressed cords to restore proper tension

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system automatically manages cord tension through the one-way clutch and rotating shaft mechanism, which self-activate when the middle rail moves upward, eliminating the need for external control or manual cord management

Inventive Principle:

Principle #25Self-service

3Ease of operation

If exposed control cords are used to manipulate rail movement, then the operation is simple, but safety concerns arise from loose and exposed cords

Engineering Contradiction:

Improvecontrol operationVSAvoidsafety hazard

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The harmful aspect of exposed cords is extracted and eliminated by automatically winding them onto the first rotating shaft through the one-way clutch mechanism, while preserving the simplicity of control operation through the existing lifting control structure

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The upward movement of the middle rail, which previously caused harmful cord loosening, is converted into a beneficial force that drives the one-way clutch to wind up the cords, transforming the problem into a self-correcting mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Maintains cord tension, prevents exposure and tangling, and ensures safety by keeping cords taut, enhancing both functionality and aesthetics of the window covering.

Implementation Method 1

The pre-stress unit comprises a spring, which is connected to the first rotating shaft in a concurrently movable manner, whereby the spring accumulates the driving force when the first rotating shaft releases the first cord, and releases the accumulated driving force to urge the first rotating shaft to receive the first cord when necessary

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS11686153B2Top-down bottom-up window covering

Publication Date: 2023.06.27 NIEN MADE ENTERPRISE CO LTD

AI summary

A top-down bottom-up window covering has a headrail, a middle rail, a bottom rail, a lifting control structure installed at the headrail, and a covering structure installed between the middle rail and the bottom rail. The lifting control structure controls a first rotating shaft and a second rotating shaft to respectively receive or release a first cord and a second cord. The first cord drives the middle rail to move, and the second cord drives the bottom rail to move. A one-way clutch and a pre-stress unit are further provided at the headrail. When the bottom rail pushes the middle rail to move upward, the one-way clutch breaks a link between the first rotating shaft and the lifting control structure. Consequently, a driving force generated by the pre-stress unit immediately drives the first rotating shaft to receive the first cord to keep the first cord taut.