Active Bale Spear Retraction for Plug-Resistant Bale Ejection

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Solution Overview

Problem

Baler implements face issues with the passive retraction system of the pawl becoming plugged with crop material, leading to incomplete withdrawal and reduced effectiveness in ejecting bales.

Innovation Solution

A bale ejection system with a frame rail, outer and inner carrier plates, and a linear actuator that actively moves the bale spear between extended and retracted positions using a linkage bar and latch systems to ensure complete disengagement from the bale.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a passive retraction system using gravity and downward forces is used to retract the pawl, then the system complexity is reduced, but the pawl cannot be fully retracted due to crop material plugging

Engineering Contradiction:

Improveretraction system complexityVSAvoidpawl retraction completeness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Instead of relying on passive gravity-based retraction, the patent applies an active hydraulic cylinder to pull the pawl rearward during the return stroke. This inverts the approach from passive to active retraction, ensuring complete withdrawal of the pawl from the bale even when crop material is present.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the passive mechanical gravity-based retraction system with an active hydraulic system. The hydraulic cylinder provides controlled mechanical force to retract the pawl, substituting the unreliable passive mechanical system with a more reliable active hydraulic actuation system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the pawl is not fully retracted, then the ejection function is maintained for the next cycle, but the pawl rips out a groove of crop material during the return stroke

Engineering Contradiction:

Improveejection cycle continuityVSAvoidcrop material damage

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The hydraulic system actively retracts the pawl during the return stroke before the next ejection cycle begins. This preliminary retraction action prevents the pawl from being partially embedded in crop material, eliminating the harmful grooving effect while maintaining readiness for the next ejection cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potentially harmful partial retraction issue into a benefit by using the return stroke period to actively and completely retract the pawl. This transforms what was previously a problematic incomplete retraction into a controlled complete retraction that prevents crop damage while maintaining ejection readiness.

Inventive Principle:

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

3Reliability

If the pawl is actively extended during the push stroke, then reliable bale ejection is achieved, but the system complexity and energy consumption increase

Engineering Contradiction:

Improvebale ejection effectivenessVSAvoidejection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hydraulic cylinder serves multiple functions: it extends the pawl forward during the push stroke to engage the bale, and retracts the pawl during the return stroke to disengage. This multi-functional use of a single actuator achieves reliable ejection while minimizing the number of separate components needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The hydraulic system provides continuous active control of the pawl throughout the entire cycle - extending during the push stroke for ejection and retracting during the return stroke for disengagement. This continuous useful action ensures reliable performance while efficiently utilizing the hydraulic system throughout the operational cycle.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS20260013441A1Bale ejection system for large square baler

Publication Date: 2026.01.15 DEERE & CO

AI summary

A bale ejection system includes an outer carrier plate an inner carrier plate, and a linear actuator attached to the inner carrier plate. A bale spear is coupled to the outer carrier plate via a linkage bar. A return stroke latch system secures the outer carrier plate relative to the frame during an initial portion of a return stroke while allowing the inner carrier plate to move along a longitudinal axis in a second longitudinal direction during the initial portion of the return stroke, whereby the linkage bar moves the bale spear along a spear axis from an extended position into a retracted position for disengaging from the bale.