Disc Mower Knife Spring Plate for Obstacle Swing-Out Protection

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Solution Overview

Problem

Existing agricultural mowers face frequent knife replacement or repair due to damage from contacting large objects, such as rocks, which can dull, shatter, or break the knives.

Innovation Solution

A disc cutter design featuring a knife with a spring plate carrying protrusions that moves to a second position when an overload force is applied, allowing the knife to swing out of the cutting path and reducing the risk of damage, with automatic return to the cutting position via centrifugal force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the knife is held rigidly in the cutting position, then cutting precision is maintained, but the knife is vulnerable to damage from obstacles

Engineering Contradiction:

Improveknife damage resistanceVSAvoidcutting position stability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The knife is designed to be movable rather than fixed, allowing it to dynamically adjust its position. The spring plate enables the knife to swing outward when encountering obstacles while maintaining cutting position stability during normal operation through centrifugal force, resolving the contradiction between damage resistance and position stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The spring plate acts as a cushioning mechanism that absorbs impact forces before they can damage the knife. By allowing controlled movement and absorbing shock, the spring plate protects the knife from obstacle damage while maintaining operational stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the knife is allowed to move freely to avoid damage, then obstacle resistance improves, but cutting precision deteriorates

Engineering Contradiction:

Improveobstacle resistanceVSAvoidcutting accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The knife transitions between two states: a stable cutting position during normal operation maintained by centrifugal force, and a protective swung-out position when obstacles are detected. This dynamic behavior allows the knife to maintain cutting precision while providing obstacle resistance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The centrifugal force that could potentially cause instability is converted into a beneficial force that automatically returns the knife to the correct cutting position after obstacle contact, ensuring both protection and precision.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If traditional rigid knife mounting is used, then device complexity is low, but knife replacement frequency increases

Engineering Contradiction:

Improveknife service lifeVSAvoidmounting mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The spring plate serves as an intermediary mechanism between the knife and the cutter bar. This simple spring-based component provides complex functionality including shock absorption, position control, and automatic return, extending knife life without significantly increasing overall device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The knife mounting system is self-regulating through centrifugal force that automatically maintains the knife in the correct cutting position during operation. The system requires no external control mechanisms, achieving reliability enhancement with minimal added complexity.

Inventive Principle:

Principle #25Self-service

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

Reduces the frequency of knife damage and replacement by absorbing overload forces, ensuring the knife remains in the cutting position and minimizes operational disruptions.

Implementation Method 1

a spring plate carrying at least two protrusions, the spring plate being biased towards the disc body such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position

Methodology Applied

Scientific EffectSpring elasticity: Elasticity

Implementation Method 2

automatic return to the cutting position via centrifugal force

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS12593750B2Agricultural disc mower with knife-retaining spring plate

Publication Date: 2026.04.07 CNH INDUSTRIAL AMERICA LLC

AI summary

A disc cutter for an agricultural implement includes: a disc body; a knife nut coupled to the disc body; a knife including a knife opening in which the knife nut is disposed, the knife being configured to rotate about a rotation axis defined by the knife nut; and a spring plate carrying at least two protrusions, the spring plate being biased towards the disc body such that in a first position the spring plate bears on the knife so a plane defined through a portion of the knife extends through the protrusions until an overload force applied to the knife forces the knife over at least one of the protrusions and moves the spring plate to a second position.