Flexible Strap Drive Coupler for Reciprocating Knife Stress Reduction

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Solution Overview

Problem

The increased length of drive couplers attached to flexible reciprocating knives in agricultural harvesting machines causes stress in the elongate bar, leading to fatigue and potential breakage under reciprocating loads.

Innovation Solution

A drive coupler system comprising elongate straps with flexible joints, including pins and resilient members, allows for flexing between the straps and the drive member, reducing stress on the elongate bar by enabling it to reciprocate while maintaining flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the drive coupler length is increased to accommodate heavier reciprocating knives, then the coupler can support the increased weight, but the stress on the elongate bar increases causing fatigue and breakage

Engineering Contradiction:

Improvereciprocating knife weightVSAvoidelongate bar durability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent applies flexible straps instead of rigid coupler structures. The flexible straps can bend and flex to accommodate the reciprocating motion and weight of the knife without transmitting harmful stresses to the elongate bar, thus supporting heavier knives while maintaining bar durability

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the mechanical properties of the coupler system by using flexible materials that can dynamically adjust their stiffness and flexibility based on operational conditions, allowing the coupler to support increased weight while accommodating the reciprocating motion without causing fatigue

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the elongate bar cross-sectional dimensions are increased to reduce flexibility, then the bar becomes more rigid and less able to flex, but this would make the bar more rigid and less able to follow land contours

Engineering Contradiction:

Improveelongate bar rigidityVSAvoidland contour following ability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent segments the coupler system into multiple flexible straps rather than using a single rigid structure. This segmentation allows each strap to independently flex and adapt to terrain variations while collectively providing the necessary structural support

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic flexible straps that can change their mechanical characteristics during operation, allowing the bar to maintain rigidity when needed for structural integrity while enabling flexibility when needed to follow land contours

Inventive Principle:

Principle #15Dynamics

3Length of moving object

If the drive coupler is made longer to reach heavier knives, then the coupler can attach to heavier knives, but the stress in the elongate bar increases causing it to break

Engineering Contradiction:

Improvedrive coupler lengthVSAvoidelongate bar stress resistance

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The flexible straps act as compliant intermediaries that can extend over longer distances without transmitting high stresses to the elongate bar, allowing the coupler to reach heavier knives positioned further away while protecting the bar from stress-induced failure

Inventive Principle:

Principle #30Flexible shells and thin films

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 effectively reduces the likelihood of the elongate bar breaking by distributing stress and allowing for flexible movement, thereby enhancing the durability and operational reliability of the reciprocating knife.

Implementation Method 1

a means for (i) flexing the first elongate strap with respect to the second elongate strap, (ii) for flexing the first elongate strap with respect to the drive member, and (iii) for flexing the second elongate strap with respect to the drive member

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The at least two flexible joints may comprise a pin, an annulus, and a resilient member

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP2820934B1Drive coupler for a reciprocating knife

Publication Date: 2017.03.01 DEERE & CO

AI summary

A drive coupler (102, 104) for coupling a reciprocating knife (106) to a drive member (112, 114) is provided, wherein the reciprocating knife (106) includes at least one elongate bar (120, 122, 180, 182) having a longitudinal extent and fixed to a plurality of blades (138), wherein the at least one elongate bar (120, 122, 180, 182) is supported on support members (140) that constrain the at least one elongate bar (120, 122, 180, 182) to reciprocate in a direction generally parallel to the longitudinal extent of the at least one elongate bar (120, 122, 180, 182), the drive coupler (102, 104) comprising: a first elongate strap (146, 162) configured to be attached to the at least one elongate bar (120, 122, 180, 182); a second elongate strap (146, 162) configured to be attached to the at least one elongate bar (120, 122, 180, 182); and a means (152, 164, 187, 189, 193, 200) for (i) flexing the first elongate strap (146, 162) with respect to the second elongate strap (146, 162), (ii) for flexing the first elongate strap (146, 162) with respect to the drive member (112, 114), and (iii) for flexing the second elongate strap (146, 162) with respect to the drive member (112, 114).