High-Resistance Cutter Bar Blade Structure for Rivet Stress

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Solution Overview

Problem

Existing cutter bar blades experience rivet shear stress and bending stress due to impact with obstacles, leading to rivet failure and reduced durability, particularly in agricultural equipment like motor mowers and combine harvesters.

Innovation Solution

The blades feature monolithic construction with multiple triangular conformations, grooves beneath beveled corners, and a high-resistance steel base component to enhance rivet strength and reduce bending stress, combined with a layered structure to withstand alternating forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If blades are fixed to the steel strip with rivets, then the blade can be securely attached to the cutter bar structure, but the rivets are subjected to shear stress from impact forces leading to rivet failure and reduced durability

Engineering Contradiction:
Improveblade attachment strengthVSAvoidrivet durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The blade is divided into multiple independent triangular blades (at least two) that are separately fixed to the steel strip. This segmentation distributes the impact forces and shear stress across multiple attachment points and individual blades, preventing single-point failure and reducing the stress on each rivet connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade structure transitions from a single flat blade to a three-dimensional arrangement with multiple triangular blades positioned at different locations on the steel strip. This spatial distribution in multiple dimensions allows for better force distribution and reduced stress concentration on individual rivets.

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

2Ease of manufacture

If the blade structure is simplified with single blade design, then the manufacturing and assembly are easier, but the blade experiences bending stress and lacks resistance to alternating forces

Engineering Contradiction:
Improveblade manufacturing simplicityVSAvoidbending resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Instead of a single blade design, the structure uses multiple triangular blades arranged on the steel strip. This segmentation provides distributed structural support that resists bending moments and alternating forces more effectively than a single blade, while each individual blade remains relatively simple in form.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cutter bar assembly functions as a composite structure combining the steel strip base with multiple triangular blade elements. This composite arrangement creates a more rigid and stress-resistant system that can withstand bending and alternating forces better than any single component could achieve alone.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3944749B1High-resistance cutter bar blade and relative cutter bar
Publication Date: 2025.10.15 BCS SPA
  • EP3944749B1 patent drawingFigure 1~2
  • EP3944749B1 patent drawingFigure 3~5
  • EP3944749B1 patent drawingFigure 6~8a

AI summary

A blade (115,155') for mainly agricultural equipment for cutting grass and the like comprising: a triangular front portion (LA), and an enlarged rear portion (LPA) for attachment to a cutter bar structure, wherein the triangular front portion (LA) laterally provides a side bevelled corner (TM) in the form of a cutting edge, located in the upper part, provided with a peripheral serration (SF) on an edge of said cutting edge (TM), facing outwardly; the enlarged rear portion (LPA) provides a pair of holes (FO) for the passage and installation on site of rivets (RI); wherein a front portion (LA") provides at least two adjacent triangular conformations (AT") extending from a rear portion (LPA") having a longitudinal dimension at least equal to a maximum dimension of the two adjacent triangular conformations, the rear portion (LPA") provides at least four holes (FO) for the passage and installation on site of rivets (RI); the at least two triangular conformations (AT"), on one of their surfaces opposite and below that in which bevelled corners (TM") are formed, provide a groove (RG) that extends from said peripheral serration (SF) to form small surface teeth.