Twist-Lock Element With Perforated Load Cell for Accurate Weight Measurement

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Solution Overview

Problem

Existing twist-lock elements for lifting and weighting containers suffer from low accuracy due to their solid structure, which restricts axial deformation, even when using sensitive Bragg lattice sensors, making it difficult to meet the refined weight measurement requirements.

Innovation Solution

The twist-lock type element incorporates a load cell with a longitudinal body that elastically elongates more than the stem under traction force, featuring a reduced cross section and transverse perforations, allowing for more significant strain gauge deformation and improved accuracy without compromising structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a solid structure is used for the twist-lock element, then structural integrity and strength are maintained, but axial deformation is restricted and measurement precision deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidweight measurement accuracy
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The twist-lock element is divided into two functional parts: a solid stem for structural integrity and a load cell with reduced cross-section for measurement. This segmentation allows each part to optimize its function - the stem provides strength while the load cell provides measurable deformation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The load cell portion of the twist-lock element has a reduced cross-section compared to the stem, creating a localized area with different mechanical properties. This local quality change enables greater axial deformation in the load cell region while the stem maintains its structural integrity.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the cross section of the load cell is reduced, then elastic elongation increases and measurement precision improves, but structural strength decreases

Engineering Contradiction:
Improvestrain gauge deformationVSAvoidstructural strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The load cell has a reduced cross-section specifically at the measurement region where strain gauges are applied, while the stem maintains its full cross-section for strength. This local quality differentiation allows the measurement region to deform more under load while the overall structure remains strong.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The element is segmented into a strong stem portion and a more compliant load cell portion. The stem handles the majority of the structural load-bearing function, while the load cell portion is designed to provide measurable elastic deformation without compromising overall structural strength.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If transverse perforations are added to the load cell, then elastic deformation capability is enhanced and measurement precision improves, but manufacturing complexity increases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidmanufacturing process
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The load cell incorporates transverse perforations that create a porous or lattice-like structure. This porous design enhances the elastic deformation capability of the load cell, allowing for greater strain under load while maintaining sufficient strength, thereby improving measurement precision.

Inventive Principle:
Principle #31Porous materials

4Reliability

If Bragg lattice sensors are used in a solid structure, then sensor sensitivity is high, but the solid structure restricts axial stretch and measurement precision deteriorates

Engineering Contradiction:
Improvesensor sensitivityVSAvoidweight measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The load cell provides a localized region with enhanced elastic properties that complements the high sensitivity of Bragg lattice sensors. By concentrating the deformation capability in the load cell region rather than throughout the entire solid structure, the system maximizes both sensor sensitivity and actual measurable deformation.

Inventive Principle:
Principle #3Local quality

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 design enhances weight measurement accuracy significantly, allowing for precise detection of traction forces while maintaining the ability to withstand nominal forces without plastic deformation, thus addressing the limitations of prior twist-lock elements.

Implementation Method 1

The longitudinal body is configured to elastically elongate to a greater extent than the twist-lock stem under the same traction force

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

at least one strain gauge is installed on the longitudinal body

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP3301422B1Twist-lock type element for locking and weighting, related method of manufacturing and device for lifting and weighting
Publication Date: 2020.04.08 EUROBIL
  • EP3301422B1 patent drawingFigure 1
  • EP3301422B1 patent drawingFigure 2
  • EP3301422B1 patent drawingFigure 3

AI summary

A twist-lock type element for locking and weighing has a load cell (4) having a longitudinal body (8) on which at least one strain gauge is installed. The longitudinal body (8) is configured to elastically elongate to a greater extent than the twist-lock stem (2) under the same traction force. The twist-lock element for locking and weighting (1) of this disclosure can be realized as a single piece element starting from a common twist-lock element without a load cell (4), with the method for manufacturing this disclosure. It is also disclosed a weighing apparatus comprising a lifting frame, commonly referred to as a "spreader", on which at least four twist-lock elements of this disclosure for lifting and weighting (1) are securely installed.