Hoist Life Calculation Using Load and Cycle Segmentation

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Solution Overview

Problem

Existing hoist life calculation methods fail to accurately estimate hoist life due to the lack of counting lowering operation times and pausing times, leading to imprecise determination of use frequency.

Innovation Solution

A hoist life calculating device that includes a controlling unit to measure and display operation situations, integrating data from current values, slippage amounts, and pausing times to classify loads and calculate remaining lifetime, incorporating a load determining unit, operating time measuring unit, operation cycle measuring unit, and loading time rate measuring unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only ground cutting times and lifting operation times are counted, then the device complexity is reduced, but the measurement precision of hoist life estimation deteriorates

Engineering Contradiction:
Improvecounting configurationVSAvoidhoist life estimation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The operation cycle counting is segmented into three distinct phases: lifting operation counting, lowering operation counting, and ground cutting counting. This segmentation allows comprehensive tracking of all hoist operations without requiring complex integrated systems, as each phase can be counted independently and then aggregated to determine total operation cycles and pausing times.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If operation cycle counting is simplified, then the ease of operation is improved, but the reliability of life estimation deteriorates

Engineering Contradiction:
Improveoperation cycle countingVSAvoidlife estimation reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary actions by setting specific counting criteria before operation begins: identifying when the hoist is lifted off the ground, when it returns to ground level, and when lowering operations occur. These preliminary classifications enable automatic, reliable counting of operation cycles and pausing times without requiring complex real-time analysis during operation.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If pausing time measurement is added, then the measurement precision of use frequency is improved, but the device complexity increases

Engineering Contradiction:
Improveuse frequency measurementVSAvoidmeasurement configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The operation cycle counting operates continuously throughout hoist usage, automatically accumulating lifting operations, lowering operations, and ground cutting events. This continuous counting process naturally captures pausing times between operations without requiring separate measurement mechanisms, maintaining simplicity while achieving comprehensive use frequency measurement.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3366634B1Hoist life calculating device
Publication Date: 2020.01.29 HITACHI IND EQUIP SYST CO LTD
  • EP3366634B1 patent drawingFigure 1
  • EP3366634B1 patent drawingFigure 2
  • EP3366634B1 patent drawingFigure 3

AI summary

A hoist life calculating device has a load calculating unit (21) that calculates a load suspended from a hoist (4) from the motor speed and the current value of a control inverter for the hoist, an operation cycle measuring unit (25) that counts both the number of lifting operations and the number of lowering operations of the hoist for each load calculated by the load calculating unit (21), an operating time measuring unit (24) that counts the operating time for each load calculated by the load calculating unit (21), and a remaining lifetime calculating unit (26) that calculates a loading rate from the operating time for each load measured by the operating time measuring unit (24) and that calculates the remaining lifetime of the device for hoisting from the obtained loading rate.