Geared Window Shade Bracket for Bead Stop Operation

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Solution Overview

Problem

Window shade systems with planetary gear systems face limitations in using bead stops due to the requirement for a chain ratio greater than 2:1, which prevents the bead stop from entering the bracket, leading to issues like continuous unraveling of the shade and potential damage when the hembar is pulled into the roller system.

Innovation Solution

A geared window shade bracket incorporating a sprocket with a ring gear, sun gear restricted from rotation, planet gears, and a planetary carrier, allowing for a chain with bead stops that can be used while maintaining a ratio less than 2:1, enabling the bead stops to function effectively and prevent over-rotation or unraveling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a planetary gear system is used to reduce operating force, then the force required to operate the shade is reduced, but the chain ratio must be greater than 2:1 which prevents the bead stop from entering the bracket

Engineering Contradiction:

Improveforce required to operate the shadeVSAvoidbead stop functionality

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The patent inverts the conventional planetary gear configuration by making the ring gear stationary and the sun gear the input, rather than the typical arrangement. This inversion allows the chain to connect directly to the sun gear, enabling the bead stop to enter the bracket while maintaining gear reduction benefits.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the gear ratio parameter to be less than 2:1, which is different from conventional planetary gear systems used in window shades. This parameter change allows the bead stop to physically enter the bracket while still providing force reduction through the planetary gear mechanism.

Inventive Principle:

Principle #35Parameter changes

2Force

If the chain ratio is greater than 2:1 to reduce operating force, then less force is needed to pull the chain, but the bead stop cannot enter the bracket causing continuous unraveling

Engineering Contradiction:

Improveforce required to pull the chainVSAvoidshade unraveling prevention

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

By inverting the planetary gear configuration and connecting the chain to the sun gear rather than the ring gear, the system achieves a chain ratio less than 2:1. This allows the bead stop to enter the bracket and reliably prevent unraveling while still providing force reduction through the planetary mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The sun gear acts as an intermediary element that the chain directly engages with. This intermediary connection allows the bead stop to reach the bracket while the planetary gears still provide mechanical advantage, mediating between the chain input and shade output.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the bead stop is made larger to prevent over-rotation, then over-rotation is prevented, but the bead stop cannot enter the bracket opening

Engineering Contradiction:

Improveover-rotation preventionVSAvoidbead stop size

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The inverted planetary gear configuration changes the spatial relationship between the chain and gear components. This allows the bead stop to enter the bracket opening and effectively prevent over-rotation, whereas the conventional configuration would block the bead stop from entering.

Inventive Principle:

Principle #13The other way round (Inversion)

4Force

If a conventional planetary gear system is used with ring gear as sprocket, then force reduction is achieved, but the chain must rotate more than one lap preventing bead stop usage

Engineering Contradiction:

Improveforce reductionVSAvoidchain rotation laps

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent inverts the conventional planetary gear arrangement where the ring gear serves as the sprocket. Instead, the sun gear becomes the sprocket that the chain directly engages with. This inversion reduces the number of chain rotations needed and allows the bead stop to function within a single rotation.

Inventive Principle:

Principle #13The other way round (Inversion)

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 allows for reduced force required to operate the shade and the ability to use bead stops, preventing over-rotation and unraveling, while enabling the use of bead stops, thus providing a familiar user experience and reducing the risk of shade damage.

Implementation Method 1

A geared window shade bracket incorporating a sprocket with a ring gear, sun gear restricted from rotation, planet gears, and a planetary carrier

Methodology Applied

Scientific EffectPlanetary gear mechanism: Epicyclic Gearing

Implementation Method 2

allowing for a chain with bead stops that can be used while maintaining a ratio less than 2:1, enabling the bead stops to function effectively

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS11230885B2Geared window shade bracket with bead stop

Publication Date: 2022.01.25 MECHOSHADE SYSTEMS LLC

AI summary

The geared window shade bracket comprises a sprocket having a ring gear on an inside circumference of the sprocket; a chain configured to be engaged with the sprocket such that, in response to pulling on the chain, the sprocket rotates; a sun gear that is configured to be restricted from rotation; one or more planet gears configured to rotate around the sun gear, wherein the one or more planet gears interface with the ring gear; and a planetary carrier configured to mate with the one or more planet gears. In response to the chain being pulled, the sprocket rotates, causing the planet gears to rotate, causing the planetary carrier to rotate, causing the hub to rotate, and causing a shade tube to rotate.