Windrow Picker Hold-Down Roller Linkage for Jam-Free Crop Flow
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Solution Overview
Problem
Existing windrow pickers suffer from crop jamming issues due to the rear hold-down roller lifting excessively when swath height increases, creating gaps in the crop flow and leading to inefficiencies.
Innovation Solution
A windrow picker design featuring a supporting frame with pivotable rockers and adjustable stops that limit the upward movement of the rear hold-down roller, ensuring it remains engaged with the crop flow even as swath height varies, using transversely extending stops to maintain contact with the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the rear hold-down roller is supported on rockers hinged to swivel arms (prior art arrangement), then the hold-down device can adapt to swath height variations, but the rear hold-down roller lifts excessively when the front hold-down roller is lifted, creating gaps in crop flow
Solution Approach 1:
The patent divides the hold-down device into two independent rocker mechanisms: a first rocker supporting the front hold-down roller and a second rocker supporting the rear hold-down roller. Each rocker operates independently with its own pivot axis and stop mechanism, preventing the coupled motion that caused excessive lifting in the prior art. This segmentation allows each roller to adapt to local swath conditions without being dragged upward by the other roller's movements.
2Productivity
If the rear hold-down roller is positioned to maintain an upper boundary for crop produce, then crop conveyance is improved, but the roller creates a free space gap when lifted, leading to crop accumulation and jamming
Solution Approach 1:
The patent implements a stop mechanism (Schranke) on the second rocker that provides mechanical feedback to limit the upward travel of the rear hold-down roller. When the roller encounters resistance or when the first rocker lifts due to increased swath height, the stop prevents excessive upward movement that would create dangerous gaps. This feedback mechanism ensures the roller maintains consistent engagement with the crop flow, preventing the accumulation and jamming problems described in the prior art.
3Device complexity
If the rockers are hinged coaxially with the front hold-down roller axis (prior art), then the structure is simplified, but the rear hold-down roller moves upward to a greater extent due to lever transmission
Solution Approach 1:
The patent introduces asymmetry in the rocker hinge arrangement by positioning the second rocker's pivot axis at a different location and orientation than the first rocker's axis. The second rocker is hinged to the first rocker in a way that creates an asymmetric lever arm relationship, specifically designed to reduce the mechanical advantage that caused excessive upward motion in the symmetric prior art arrangement. This asymmetric configuration maintains structural simplicity while fundamentally changing the motion characteristics to prevent over-lifting.
Data Source
AI summary
A windrow picker is equipped with a supporting frame movable in a forward direction across a field. The frame having mounted thereon a pick-up drum, an output conveyor and a first rocker. The first rocker is mounted at its upper, rearward end on the frame so as to be pivotable about a transversely extending axis of rotation. A second rocker is hinged to the first rocker at the lower, front end of the first rocker at a mounting so as to be pivotable about a transversely extending axis. The second rocker supports a front, lower hold-down roller and a rear, upper hold-down roller. The lowest possible position of the second rocker is limited by a stop which cooperates with a counter stop. The counter stop is attached to the frame.