Angular Drive Flat Belts With Fleet Angle to Limit Sidewall Abrasion

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Solution Overview

Problem

Flat belts in angular drive systems are prone to premature failure due to aggressive twist geometries, which cause uneven tension distribution and sidewall abrasion, leading to reduced service life and limited design compactness.

Innovation Solution

Implementing a twisted geometry in flat belts with a complimentary fleet angle to normalize tension distribution, allowing for more aggressive twist ratios such as 7:1 with minimal service life penalty, by misaligning the geometric centerline of the belt at a specific fleet angle, thereby reducing asymmetry in tension and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a flat belt is subjected to aggressive twist geometries to achieve compact design envelopes, then the design compactness is improved, but the service life is significantly reduced due to uneven tension distribution and sidewall abrasion

Engineering Contradiction:

Improvedesign envelopeVSAvoidservice life

Core Design Contradiction:

Volume of moving objectVSDuration of action of moving object

Solution Approach 1:

The patent applies asymmetry by intentionally introducing a fleet angle (misalignment) between the belt centerline and sheave centerline. This asymmetric configuration creates a compensating tension distribution that counteracts the uneven tension caused by aggressive twist geometries, thereby extending belt service life while maintaining compact design envelopes with twist ratios as low as 7:1

Inventive Principle:

Principle #4Asymmetry

2Volume of moving object

If the twist ratio is increased to achieve more compact design envelopes, then the design compactness is improved, but the tension distribution becomes more uneven leading to premature belt failure

Engineering Contradiction:

Improvedesign envelopeVSAvoidtension distribution

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent uses asymmetric sheave positioning with a specific fleet angle to create a compensating effect. The misalignment generates a tension distribution pattern that opposes and balances the uneven tension caused by high twist ratios, enabling stable operation with twist ratios down to 7:1

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the geometric parameters of the belt-sheave system by introducing a controlled fleet angle and specific sheave offset distances. These parameter adjustments transform the tension distribution characteristics, converting the destabilizing effect of aggressive twists into a balanced state

Inventive Principle:

Principle #35Parameter changes

3Duration of action of moving object

If a fleet angle is introduced to normalize tension distribution in twisted belts, then the service life is extended, but the belt is subjected to additional sidewall contact with sheave flanges causing abrasion

Engineering Contradiction:

Improveservice lifeVSAvoidsidewall abrasion

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful sidewall contact into a beneficial force by carefully designing the fleet angle and sheave flange geometry. The sidewall contact that would normally cause abrasion is transformed into a guiding mechanism that maintains proper belt alignment and distributes loads more evenly, thereby extending service life even with aggressive twist ratios

Inventive Principle:

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

Data Source

PatentUS11835132B2Normalizing tension distribution and minimizing sidewall abrasion within angular drive belt systems

Publication Date: 2023.12.05 LIFTWAVE INC DBA RISE ROBOTICS

AI summary

This disclosure relates to methods and apparatuses of employing belts for an angular drive. A twisted geometry is applied to a first free span of the belt. A sheave supports the first free span of the belt at a first extremity of the first free span and sheave is at least one of positioning and orienting the rotating sheave or the driven sheave so as to misalign a geometric centerline of the first free span of belt at a given fleet angle with respect to a second extremity of the first free span.