Roman Shade Cord Catch Structure for Tangled-Free Winding

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Solution Overview

Problem

Existing Roman blinds face issues with uneven winding of pull cords due to obstacles, leading to tangling and manual intervention required for adjustment, especially when the curtain is tilted by an obstruction, causing inconsistent tension in drawstrings.

Innovation Solution

A semicircular partial ring body driver is clamped onto the winding shaft with a long-nose or wedge-shaped hook-like section, ensuring secure grip and release of pull cords, allowing them to wind and unwind without tangling, and can be easily attached or removed based on the shaft section, ensuring problem-free operation and orderly winding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pull cords are gripped by catches on the winding shaft to enable winding during gathering, then the curtain can be gathered effectively, but when the curtain is tilted by an obstacle causing uneven tension, the pull cords slide out of the driver during deshirring, requiring manual intervention

Engineering Contradiction:
Improvegathering efficiencyVSAvoidoperational reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The driver is designed to dynamically change its grip state based on rotation direction. During gathering (clockwise rotation), the driver grips the pull cord through its curved surface and groove. During deshirring (counter-clockwise rotation), the driver automatically releases the pull cord. This dynamic behavior eliminates the need for manual intervention while maintaining gathering efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The driver engages and disengages the pull cord in periodic cycles corresponding to the rotation direction changes. The curved surface and groove create a periodic gripping action during gathering, followed by automatic release during deshirring, enabling continuous automated operation without manual resetting.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If the pull cords are always under tension when the curtain is untangled, then the pull cords can be gripped by the driver disc, but when the curtain is tilted by an obstacle, the pull cords become relaxed in some sections and slide out of the driver

Engineering Contradiction:
Improveautomatic operationVSAvoidwinding uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The driver features an asymmetric curved surface and groove configuration that creates different engagement characteristics for tensioned and relaxed pull cords. The asymmetric design ensures that even when pull cords have varying tension due to obstacles, the driver maintains consistent gripping during gathering and reliable release during deshirring, ensuring uniform winding.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If the driver is fixed on the winding shaft, then it can reliably grip and carry the pull cord, but it cannot be easily removed or repositioned for different shaft sections or requirements

Engineering Contradiction:
Improvegrip reliabilityVSAvoiddriver positioning flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The driver is designed as a separate, modular component that can be independently positioned and secured at different locations on the winding shaft. This segmentation allows the driver to be removed and repositioned to accommodate different shaft sections or operational requirements while maintaining reliable gripping performance at each position.

Inventive Principle:
Principle #1Segmentation

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 ensures secure and consistent winding of pull cords, preventing tangling and allowing for smooth operation even when the curtain is unevenly lowered, eliminating the need for manual intervention and ensuring the curtain can be adjusted without tangling issues.

Implementation Method 1

the partial ring body covering at least half the circumference of the winding shaft encompasses and has an inner diameter which corresponds approximately to the outer diameter of the take-up shaft and is held on the take-up shaft by means of a press fit

Methodology Applied
Scientific EffectPress fit: Friction

Data Source

PatentEP1857024B1Roman shade and drawing cord catch for this shade
Publication Date: 2013.12.04 PROFILUX
  • EP1857024B1 patent drawingFigure 1
  • EP1857024B1 patent drawingFigure 2~4
  • EP1857024B1 patent drawingFigure 5~6

AI summary

Operated by an electric motor or by hand, a shaft (20) has a carrier (40) on its periphery to grasp a pull cord(s) (30) near a pull cord section (31) formed by lug-shaped reversing elements (35) and running parallel to the longitudinal direction of the shaft. The carrier consists of a molded body (45) fitted directly on the shaft's wall surface (20a).