Cord Lock Assembly Friction Reduction

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Solution Overview

Problem

Current cord lock assemblies for retractable shades require multiple direction changes for the pull cord, leading to increased friction and resistance, and often necessitate moving the pull cord left or right to engage the locking mechanism, which can be cumbersome, especially when the shade assembly is adjacent to corners or large furniture.

Innovation Solution

A direct drive cord lock assembly that reduces friction and resistance by allowing a single pull cord to extend or retract the rail, eliminating the need to move the pull cord left or right to engage the locking mechanism, featuring a spool and cam system that minimizes contact surfaces and uses a roller to pin the pull cord for locking, reducing the amount of rail drop and enhancing ease of operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple direction changes are used for the pull cord to enable retraction and extension, then the cord lock assembly can control the rail movement, but the amount of friction and resistance increases

Engineering Contradiction:

Improveease of pull cord operationVSAvoidfriction and resistance

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The cord lock assembly is divided into separate functional components: a pull cord channel for direct pull cord movement, a spool for cord winding, and a cam mechanism for locking. This segmentation allows the pull cord to move directly without multiple direction changes, reducing friction while maintaining control functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cam mechanism acts as an intermediary between the pull cord and the locking function. The cam converts the linear motion of the pull cord into the rotational motion needed for locking, eliminating the need for multiple direction changes and reducing friction in the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the pull cord must be moved left or right to engage the locking mechanism, then the locking function can be achieved, but the operation becomes difficult when the shade assembly is adjacent to corners or large furniture

Engineering Contradiction:

Improvelocking mechanism engagementVSAvoidease of locking engagement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Instead of requiring the pull cord to move laterally (left or right) to engage the locking mechanism, the design inverts the approach: the pull cord moves in a straight line toward the headrail, and the cam mechanism automatically converts this motion into locking action. This inversion eliminates the need for lateral movement, making operation feasible even in constrained spaces near corners or furniture.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If multiple direction changes are implemented in the pull cord path, then the cord lock can function, but the complexity of the device increases

Engineering Contradiction:

Improvecord lock functionalityVSAvoidcord path configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pull cord channel and locking mechanism are merged into a single integrated assembly. The pull cord channel is positioned to receive the pull cord directly, and the cam mechanism is integrated within the same housing, eliminating the need for separate direction change components and simplifying the overall device structure.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If a traditional cord lock assembly is used with multiple direction changes, then the rail can be extended and retracted, but the amount of rail drop increases when locking

Engineering Contradiction:

Improverail extension and retractionVSAvoidrail position accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The cam mechanism is designed to engage the pull cord and initiate locking action before the full locking position is reached. This preliminary engagement prevents excessive rail drop by maintaining tension and control throughout the locking process, ensuring precise final positioning of the rail.

Inventive Principle:

Principle #10Preliminary action

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 more efficient and user-friendly operation by reducing friction and resistance, allowing for even lift across the rail, enhancing child safety, and preventing rail drop when locking, while maintaining a clean and aesthetically pleasing appearance.

Implementation Method 1

a roller rotatably positioned on the pin

Methodology Applied

Scientific EffectRoller rotation: Roller

Implementation Method 2

A cam is positioned in the pull cord channel and includes a pin extending from the cam

Methodology Applied

Scientific EffectCam mechanism: Cam

Implementation Method 3

reduces friction and resistance by allowing a single pull cord to extend or retract the rail

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS9388632B2Cord lock assembly

Publication Date: 2016.07.12 HUNTER DOUGLAS INC

AI summary

A cord lock assembly for a shade assembly is provided. The cord lock assembly may include a spool rotatably attached to a housing, with the housing defining a pull cord channel. A pull cord may be provided that extends through the pull cord channel and wraps at least partially around the spool. The pull cord channel may include a roller configured to interact with the pull cord and a rear wall of the pull cord channel such that it may move between a locked and an unlocked position based at least in part by the angle at which the pull cord is held relative to a plane defined the shade assembly.