Preloaded Coupling for Dynamic Load Damping and Fatigue Reduction

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Solution Overview

Problem

Existing systems for mitigating fatigue and dynamic amplification of loads in objects, such as drive units and solar collectors, face challenges including high costs, maintenance issues, and loss of positional information due to conventional approaches like increased design margins, shear pins, and slip clutches, which are inadequate for handling cyclic and impulsive loads.

Innovation Solution

The implementation of a load mitigation system that incorporates pre-loading mechanisms with detent release and spring-damper systems, providing tunable damping and high stiffness to absorb and dampen loads, thereby reducing fatigue cycles and dynamic amplification, and maintaining positional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If design margins or safety factors are increased to handle dynamic loads, then reliability is improved, but weight and cost increase

Engineering Contradiction:

ImprovereliabilityVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies beforehand cushioning by incorporating energy absorption elements (such as elastomeric materials, springs, or dampers) into the coupling system that are pre-configured to absorb and dissipate dynamic loads before they can cause damage to the drive unit. This allows the system to maintain lower design margins while achieving the same reliability, thereby reducing weight.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If shear pins are used to protect against excessive loads, then reliability is improved, but maintenance requirements increase and downtime occurs

Engineering Contradiction:

ImprovereliabilityVSAvoidease of repair

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces disposable shear pins with reusable energy absorption elements that can withstand multiple load cycles without failing. These elements are designed to be durable and maintainable, eliminating the need for frequent replacements and associated downtime while preserving the protective function against excessive loads.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If slip clutches are used to limit torque, then reliability is improved, but positional accuracy is lost due to shaft rotation

Engineering Contradiction:

ImprovereliabilityVSAvoidmeasurement precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary energy absorption element between the driving and driven shafts that limits torque transmission without allowing relative rotation. This intermediary element (such as a elastomeric coupling or spring-mounted damper) absorbs excess energy while maintaining rigid positional coupling, thereby preserving measurement precision while providing protective torque limiting.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If elastomeric materials are used in jaw couplings to absorb load, then reliability is improved, but manufacturing precision requirements increase

Engineering Contradiction:

ImprovereliabilityVSAvoidmanufacturing precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the parameters of the elastomeric energy absorption elements (such as durometer hardness, geometry, and pre-compression) to achieve effective load absorption with relaxed manufacturing tolerances. By carefully selecting and tuning these parameters, the system achieves reliable performance without requiring high-precision manufacturing, thereby reducing cost while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

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

This approach effectively extends the life of drive units, reduces costs, and enhances safety by minimizing peak design loads and eliminating worst-case conditions, while maintaining structural integrity and positional accuracy.

Implementation Method 1

spring-damper systems, providing tunable damping and high stiffness to absorb and dampen loads

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

spring-damper systems, providing tunable damping and high stiffness to absorb and dampen loads

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentUS10982738B1Coupling system for reducing fatigue and dynamic amplification of loads in objects

Publication Date: 2021.04.20 UNIVERSITY OF ALABAMA

AI summary

A coupling system can include an energy transfer device and a load mitigation system. The energy transfer device can include a shaft, gear, chain or piston-cylinder arrangement to transfer the energy from a power supply to an object to be moved. The load mitigation system can be used to limit or prevent the transfer of forces from the object to the drive unit as a result of external loads being applied to the object. The load mitigation system can be pre-loaded such that external loads on the object having an excessive impulsive or resonant cyclic force greater than the pre-load force on the load mitigation system are reduced and only partially transferred to the energy transfer device and power supply. The load mitigation system can dampen both resonant loads and impulsive impact loads occurring at the object thereby preventing damage and extending life.