Draper Canvas Seal with Cutter Bar Element
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Solution Overview
Problem
Existing draper header designs fail to provide an effective seal between the draper canvas and the cutter bar, leading to material entry and potential damage, as seen in alternative arrangements like U.S. Pat. No. 6,351,931, which did not offer significant improvements over previous designs.
Innovation Solution
A draper canvas with a resilient strip attached to the front edge, extending rearwardly from the cutter bar, and a guide bead on the inner surface, along with transverse slats, to create a seal and prevent misalignment, enhancing the sealing and guiding mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional draper canvas without additional sealing elements is used, then the device complexity is low, but material entry occurs between the cutter bar and canvas causing damage
Solution Approach 1:
The canvas is segmented into functional zones: a guiding zone with a bead for alignment, a sealing zone with a resilient strip for material prevention, and a supporting zone with slats for structural integrity. This segmentation allows each zone to perform its specific function effectively while maintaining overall system reliability.
Solution Approach 2:
A resilient strip is introduced as an intermediary sealing element between the cutter bar and the canvas. This intermediary component fills the gap and prevents material entry without requiring complex integration into the canvas itself, thus improving sealing while managing complexity.
2Object-affected harmful factors
If additional sealing elements like resilient strips are added to the canvas, then material entry is prevented, but the manufacturing complexity increases
Solution Approach 1:
A resilient strip in the form of a flexible thin film is attached to the canvas to create the sealing surface. This flexible element conformally contacts the cutter bar surface, providing effective sealing against material entry while being relatively simple to manufacture and attach compared to rigid sealing structures.
Solution Approach 2:
The canvas assembly becomes a composite structure combining the base canvas material with attached resilient sealing strips and guiding beads. This composite approach allows each material to be optimized for its specific function while maintaining ease of manufacture through modular attachment rather than monolithic construction.
3Manufacturing precision
If guide beads are added to prevent misalignment, then the positioning accuracy improves, but the device complexity increases
Solution Approach 1:
The guide bead is designed to be self-aligning, utilizing the geometry of the bead and its interaction with the cutter bar edge to automatically position the canvas correctly during operation. This self-service mechanism provides precise alignment without requiring complex active control systems or additional adjustment mechanisms.
Data Source
AI summary
A crop harvesting header with a cutter bar and a draper assembly has a draper canvas with a plurality of transverse slats with a resilient strip across a front edge of the outer surface in front of the front end of the slats to cooperate with a rearwardly projecting element of the cutter bar extending over the upper run of the draper canvas to engage the upper surface of said strip to form a seal to inhibit entry between the cutter bar and the draper canvas of materials carried by the cut crop. There is also provided a bead on the canvas on the surface opposite the strip within the width of the strip. The arrangement can be symmetrical with a strip at each of the front and rear edges spanned by the slats extending between them, with beads on each edge opposite the front and rear strips respectively.