Tensile Stress Indicator Spring Element Design

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Solution Overview

Problem

Existing load indicators for lashing straps are expensive, difficult to read at high lashing forces, and cannot accurately represent overload conditions due to the geometric changes of C-shaped spring elements and the need for additional display amplification.

Innovation Solution

A one-piece or two-piece spring element with convex, elastically deformable arch sections and integrated indicator displays that change distance with applied force, allowing for clear visual indication of tensile stress and overload, reducing material usage and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a C-shaped spring element is used as a load indicator, then the device can indicate tensile stress through geometric deformation, but at high lashing forces the spring itself changes geometrically in such a way that a changed display is no longer easily perceptible to the human eye

Engineering Contradiction:
Improveload indication accuracyVSAvoidvisual detectability
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent transitions from a one-dimensional C-shaped spring deformation to a two-dimensional planar spring element with indicator markings. The spring element (1) is designed as a flat component with multiple indicator markings (2, 3, 4, 5) that move relative to each other in a plane, providing better visual separation and detectability at all load levels.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The spring element is divided into multiple segments with individual indicator markings (2, 3, 4, 5) instead of a single continuous C-shape. Each marking can be independently positioned and read, allowing for better visual distinction and measurement precision across the full range of tensile forces.

Inventive Principle:
Principle #1Segmentation

2Difficulty of detecting and measuring

If additional display amplification is added to make the display perceptible at high forces, then visual detectability is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvevisual detectabilityVSAvoiddevice structure
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The indicator markings (2, 3, 4, 5) are integrated directly into the spring element (1) as a single unified component. This eliminates the need for separate display amplification mechanisms while maintaining excellent visual detectability, as the markings are positioned to provide clear separation and readability across all load conditions.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a C-shaped spring element is used, then the device can indicate tensile stress, but the spring remains in its compressed end position even in the event of an overload, preventing overload representation

Engineering Contradiction:
Improveoverload detectionVSAvoidspring position stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The spring element is designed with multiple indicator markings that can assume different relative positions dynamically. In the unloaded state, markings are separated; under increasing load, they move closer; and under overload, they can overlap or collide, providing dynamic visual feedback that clearly indicates when the maximum load capacity is exceeded.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If two components (spring element and molded part) are used to form the load indicator, then the functional requirements are met, but the manufacturing cost increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The spring element and indicator markings are combined into a single monolithic component (1). This eliminates the need for separate molded parts while maintaining all necessary functional capabilities, including tensile stress indication and overload detection, thereby reducing manufacturing complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution provides a cost-effective, easily readable load indicator that can accurately display tensile stress and detect overloading, with reduced material usage and improved visibility of prestressing forces.

Implementation Method 1

a one-piece or two-piece spring element with two opposing convex, elastically deformable arch sections

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3971031A1Device for indicating a tensile stress
Publication Date: 2022.03.23 SPAN SET GES FUER TRANSPORTSYST & TECHN BAENDER MIT BESCHRAENKTER HAFTUNG & KOMMANDITGES
  • EP3971031A1 patent drawingFigure 1~2
  • EP3971031A1 patent drawingFigure 3~5
  • EP3971031A1 patent drawing

AI summary

The invention relates to a device for indicating a tensile stress on a flexible load element, wherein the device can be arranged in its longitudinal extension in the tensile direction of the flexible load element in a loop or eyelet of the flexible load element, and wherein the device has a one- or two-piece spring element with two opposing convex, elastically deformable arc sections which lie against each other at their end regions, a spring interior is formed by the arc sections, and at least one indicator display is arranged in the spring interior on the inner surfaces of each of the two arc sections.