Ballast Weight Calculation Using Pressure Transducers

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Solution Overview

Problem

Manual data entry for crane load moment limitation can lead to errors and inaccuracies in calculating the ballast weight, affecting crane stability, as operators may enter incorrect data or find it difficult to retrieve necessary information.

Innovation Solution

An apparatus with pressure transducers in ballasting cylinders and an evaluation unit calculates the mass moved by the cylinders, excluding friction forces, and performs a plausibility check on manually entered data to ensure accuracy and reduce operator errors, potentially operating autonomously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual data entry is used for ballast weight, then operator control is maintained, but errors and inaccuracies occur in calculating ballast weight

Engineering Contradiction:

Improveaccuracy of ballast weight dataVSAvoidmanual data entry requirement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs self-measurement of ballast weight using pressure transducers integrated into the ballasting cylinders. The evaluation unit automatically calculates the ballast weight from pressure measurements during cylinder retraction and extension, eliminating the need for manual operator input and thereby preventing entry errors while maintaining system control

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The manual data entry process is replaced by an automated measurement system using pressure transducers and electronic evaluation. The mechanical/manual operation of entering data is substituted with automatic pressure-based measurement and electronic calculation, improving reliability without compromising operational control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If pressure transducers are arranged outside ballasting cylinders, then installation is simpler, but measurement accuracy decreases and damage risk increases

Engineering Contradiction:

Improvepressure measurement accuracyVSAvoidpressure line configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure transducers are integrated directly into the ballasting cylinders, with the transducer housing nested within the cylinder structure. This arrangement provides direct pressure measurement at the source while protecting the transducers within the cylinder's structural envelope, eliminating the need for external pressure lines and improving measurement accuracy

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The pressure transducer assembly is merged with the ballasting cylinder structure, combining the pressure measurement function with the existing hydraulic cylinder. This integration eliminates separate pressure lines and external transducer mounting, reducing complexity while enhancing measurement accuracy through direct pressure sensing

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If friction forces are included in mass calculation, then calculation is simpler, but measurement accuracy decreases

Engineering Contradiction:

Improveballast weight calculation accuracyVSAvoidfriction force compensation

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs measurements in both retraction and extension directions and uses the evaluation unit to compensate for friction forces by analyzing the pressure differences between opposing movements. This feedback-based approach cancels out friction effects, providing accurate ballast weight calculation while maintaining manageable system complexity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The weighing process utilizes periodic retraction and extension movements of the ballasting cylinders. By performing measurements during both phases and comparing results, the system periodically compensates for friction forces, achieving high measurement accuracy without requiring complex continuous compensation mechanisms

Inventive Principle:

Principle #19Periodic action

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 solution enhances measurement accuracy, reduces the risk of damage to pressure transducers, and ensures precise calculation of ballast weight, improving crane stability by automating the entry process and preventing unstable conditions.

Implementation Method 1

each comprise at least one pressure transducer in the region of the piston and/or rod side

Methodology Applied

Scientific EffectPressure detection:

Data Source

PatentUS11542125B2Device and method for weighing a ballast on a crane and corresponding crane

Publication Date: 2023.01.03 LIEBHERR WERK EHINGEN

AI summary

The invention relates to an apparatus for ballast weighing on a crane, comprising at least two ballasting cylinders that are equipped to lift/lower the ballast and that each comprise at least one pressure transducer in the region of the piston and/or rod side, and comprising at least one evaluation unit that is equipped to calculate the mass moved by the ballasting cylinders from the pressures detected by the pressure transducers on retraction and/or extension of the ballasting cylinders, excluding the friction forces occurring in the ballasting cylinders. The invention furthermore is directed to a method for calculating the ballast weight of a crane by means of a corresponding apparatus.