Rescue Hoist Secondary Brake Testing Without Drive-Train Wear

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Solution Overview

Problem

Existing rescue hoists lack a method to test the secondary brake without causing adverse wear or fatigue, which is crucial for meeting the stringent 1×10−9 per flight hour failure rate requirement set by AS6342, as they are a new component in the hoist system.

Innovation Solution

A computer-implemented method and controller are used to test the secondary brake by modifying the motor drive control to reduce torque output through current reduction or phase advance, ensuring the cable drum stops without engaging the secondary brake, thus avoiding wear on the drive train components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the secondary brake is tested using conventional methods, then the brake's functionality can be verified, but wear and fatigue are induced on the drive train components

Engineering Contradiction:

Improvesecondary brake functionality verificationVSAvoidwear and fatigue on drive train

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The test method changes the motor operating parameters by increasing phase advance angle and reducing duty cycle to decrease torque output to near-zero levels, allowing secondary brake testing without inducing wear on drive train components

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts motor control parameters during the test sequence, transitioning between different torque levels to enable brake engagement while maintaining minimal stress on mechanical components

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If the motor torque output is reduced to test the secondary brake, then wear on the drive train is avoided, but the cable drum may not stop reliably

Engineering Contradiction:

Improvewear on drive trainVSAvoidcable drum stopping capability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The primary brake is engaged beforehand to provide initial deceleration and support, preparing the system for secondary brake engagement while the motor provides minimal torque to ensure reliable stopping without excessive wear

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The primary brake acts as an intermediary that shares the load during the transition phase, enabling the secondary brake to engage and stop the drum reliably while both brakes work together to distribute mechanical stress

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12460996B2Method for testing the operation of a next generation rescue hoist

Publication Date: 2025.11.04 GOODRICH ACTUATION SYST

AI summary

A method for testing a rescue hoist that includes motor drive train. The motor drive train includes: a primary load brake, a secondary load brake and a cable drum comprising a cable. The method includes: reeling the cable out of the cable drum followed by reeling the cable in at a speed that is sufficient to disengage the primary load brake and verifying that the cable drum is rotating. When verified that the cable drum is rotating, the method further comprises the step of decreasing the motor torque output, before engaging the secondary brake. The method further comprises the step of verifying that said cable drum has stopped rotating, and if it is verified that the cable drum has stopped rotating, disengaging the secondary brake, restoring torque motor output and then reeling said cable is reeled into the homed position and the test is confirmed to have been passed.