Load Weight Determination via Hydraulic Pressure in Loading Machines

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Solution Overview

Problem

Existing methods for determining the weight of loads picked up by loading machines are inaccurate and costly, often requiring costly retrofitting of measuring elements that can be damaged by mechanical loads and lack universal usability across different machines.

Innovation Solution

The method involves using measuring elements to determine the operating fluid pressures of hydraulic support elements, which are then processed in a control unit to calculate the weight of the load, utilizing existing pressure-actuated support elements to achieve high precision without the need for additional, costly retrofitting, and integrating the weight into handling cycles for accurate total weight determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If measuring elements are installed to determine load weight, then measurement precision is improved, but device complexity and acquisition costs increase

Engineering Contradiction:
Improveload weight measurement precisionVSAvoidmeasuring element arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The support elements themselves serve the dual function of mechanically supporting the loading machine and providing measurement data through integrated pressure sensors. The existing hydraulic system's pressure measurements are reused for weight determination, eliminating the need for separate measuring elements and reducing device complexity while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pressure sensors in the hydraulic support elements perform multiple functions: monitoring support forces for machine stability and simultaneously providing data for load weight calculation. This multi-functionality reduces the need for additional dedicated measuring elements, thereby reducing device complexity and acquisition costs while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If additional measuring elements are added to determine load weight, then measurement precision is improved, but acquisition costs increase

Engineering Contradiction:
Improveload weight measurement precisionVSAvoidacquisition cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The hydraulic system's existing pressure sensors are utilized for weight measurement purposes, making the system self-sufficient. No additional dedicated weight measurement hardware is required, as the pressure data from the support elements' hydraulic systems is repurposed for load weight calculation, thereby reducing acquisition costs while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the parameter being measured from direct force measurement to pressure measurement in the hydraulic fluid. Since pressure sensors are already present in the hydraulic system for other functions, this parameter change allows weight determination using existing infrastructure, reducing acquisition costs while achieving the required measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If measuring elements are installed to determine load weight, then measurement precision is improved, but reliability decreases due to potential damage from mechanical loads

Engineering Contradiction:
Improveload weight measurement precisionVSAvoidmeasuring element durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The hydraulic pressure sensors serve the dual purpose of monitoring hydraulic system pressure and providing weight measurement data. Since these sensors are already part of the hydraulic system's pressure monitoring infrastructure, they are designed to withstand the system's operating conditions, thereby improving reliability while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The hydraulic fluid acts as an intermediary that transmits both the mechanical support force and the weight information to the pressure sensors. The sensors measure the pressure in the hydraulic fluid, which indirectly reflects the load weight without being directly exposed to the mechanical stresses of the load itself, thereby improving reliability while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides high measurement accuracy and lower acquisition costs by utilizing existing support elements to determine load weights based on internal pressures, reducing the risk of damage and ensuring precise tracking of loads over time, with the ability to easily retrofit existing machines.

Implementation Method 1

measuring elements (8a to 8d) are used to determine operating fluid pressures of individual support elements (4a to 4d) that hydraulically support the loading machine (1)

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

The individual operating fluid pressures are added up in a control unit (9) and a known or previously determined load constant can be converted into a total weight of the loading machine

Methodology Applied
Scientific EffectHydraulic pressure-force relationship: Hydraulic Press

Data Source

PatentEP3546414B1Method for determining the weight of a load held by a loading machine and loading machine for same
Publication Date: 2021.12.15 TEREX DEUT
  • EP3546414B1 patent drawingFigure 1
  • EP3546414B1 patent drawingFigure 2
  • EP3546414B1 patent drawingFigure 3

AI summary

The invention relates to a method for determining the weight of a load picked up by a loading machine (1), in which operating fluid pressures (EP1 to EP4) of individual support elements (4a to 4d) that hydraulically support the loading machine (1) in an operating state on a surface (U) are determined by means of measuring elements (8a to 8d). In order to create a method for determining the weight of a load picked up by a loading machine that offers high measurement accuracy at a lower acquisition cost, it is proposed that the operating fluid pressures (EP1 to EP4) be summed in a control unit (9) and converted into a total weight (GG) of the loading machine (1) using a known or previously determined load constant (L). From the total weight (GG) and with knowledge of the dead weight (EG) of the loading machine (1), the weight of a load picked up by the loading machine (1) is determined.wherein the determined weight of the load picked up by the loading machine (1) is related in the control unit (9) to a handling cycle of the loading machine (1), the handling cycle begins with the closing of a load-handling device of the loading machine (1) and ends with the opening of the load-handling device, and the weight determined for each handling cycle is added in the control unit (9) to obtain a total handling weight resulting from a predetermined number of handling cycles. The invention also relates to a loading machine for this purpose.