Cycloidal Drive Window Treatment Mechanism

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Solution Overview

Problem

Existing window treatment systems, such as roller shades, face challenges with larger sizes and weights requiring stronger clutch mechanisms, which increase complexity and cost due to the need for larger pulleys or additional springs, and existing solutions like planetary gears are costly and may not provide sufficient mechanical advantage.

Innovation Solution

A cycloidal drive mechanism using a pulley with a disc-shaped body and a motion transmission element, including a circular rib off-center from the rotational axis, and a rotor with projections and control elements, providing a mechanical advantage and resisting torsional forces without transmitting them back to the input member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a larger pulley is used to increase mechanical advantage, then the mechanical advantage is improved, but the space required increases and aesthetic appearance deteriorates

Engineering Contradiction:

Improvemechanical advantageVSAvoidspace required

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The patent changes the fundamental parameter of the drive mechanism from a simple pulley system to a cycloidal drive mechanism. This allows achieving high mechanical advantage (10:1 or higher) through the cycloidal geometry and gear ratio rather than through a large pulley diameter, thus resolving the contradiction between mechanical advantage and space requirement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional pulley-based mechanical advantage system with a cycloidal drive mechanism that uses eccentric rotation and gear engagement. This substitution enables compact high-ratio mechanical advantage without requiring a large pulley, thereby resolving the space vs. mechanical advantage contradiction

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If additional springs are added to strengthen the clutch mechanism, then the locking capability is improved, but the device complexity increases

Engineering Contradiction:

Improvelocking capabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the spring-based locking mechanism from the clutch system. The cycloidal drive mechanism inherently provides mechanical advantage and positioning capability without requiring additional springs, thus improving reliability while reducing structural complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cycloidal drive mechanism is self-sufficient in providing mechanical advantage and positioning. The eccentric rotor and cycloidal gear geometry automatically provide the necessary mechanical benefit without requiring external springs or additional locking components, resolving the contradiction between reliability and complexity

Inventive Principle:

Principle #25Self-service

3Power

If planetary gears are used to achieve mechanical advantage, then the mechanical advantage is improved, but the manufacturing cost and assembly complexity increase

Engineering Contradiction:

Improvemechanical advantageVSAvoidmanufacturing cost

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The patent segments the cycloidal drive into simpler components: a cycloidal gear, an eccentric rotor, and a stationary housing. This segmentation allows each component to be manufactured independently using standard machining processes, avoiding the high cost and complexity of assembling precision planetary gear sets while achieving comparable or superior mechanical advantage

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 cycloidal drive mechanism offers a compact, aesthetically acceptable solution with increased mechanical advantage, reducing the need for additional springs and avoiding the complexity and cost of planetary gears, while effectively managing rotational forces without requiring additional braking mechanisms.

Implementation Method 1

a rotor and a guard cooperating with the guard to form a cycloidal drive that transmits rotational motion from the input member to the output member

Methodology Applied

Scientific EffectCycloidal motion:

Data Source

PatentUS9033841B2Window treatment operating apparatus with cycloidal drive

Publication Date: 2015.05.19 ROLLERASE INC

AI summary

An apparatus for selectively activating a window treatment includes an input member, such as a pulley activated by a bead chain, an output member such as a sleeve activating a mandrel, a stationary guard for mounting the window treatment and a rotor. The rotor, pulley, and stationary base are coupled to form a cycloid drive, wherein rotation of the pulley causes the rotor to precess with respect to the pulley.