Articulated Cutting Head Linkage for Sod Harvesters
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Solution Overview
Problem
Current sod harvesting machine cutting head designs face issues with maintaining uniform slab thickness due to ground undulations, lack of transverse stiffness, and inadequate lifting mechanisms, leading to poor quality slabs and increased maintenance needs.
Innovation Solution
An articulated cutting head and conveyor mount featuring a five-bar linkage system that includes a head boom, cutting head frame, lower yoke, and stabilizing bars, allowing the cutting head to tilt and rotate for ground-following, providing high transverse stiffness, and enabling the conveyor to be raised and lowered with the cutting head for improved maneuverability and service access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple spindle and bearing arrangement is used to move the cutting blade with the contour of the ground, then the device complexity is reduced, but the transverse stiffness is insufficient causing skewing of the blade trajectory and ragged edges on the slab
Solution Approach 1:
The cutting head is divided into multiple rigid segments (blade assembly, ground reference roller, stabilizing bars) connected by articulated linkages. This segmentation allows each component to maintain its structural integrity and stiffness while enabling controlled movement through the linkage joints, resolving the conflict between complexity and stiffness.
Solution Approach 2:
The cutting head employs composite structural design combining rigid components (steel frame, bars, and blade assembly) with articulated linkage mechanisms. The rigid components provide necessary transverse stiffness, while the linkage joints enable ground-following motion, achieving both stiffness and adaptability.
2Adaptability or versatility
If the ground reference roller is positioned several inches aft of the spindle, then the cutting head can follow ground contours, but a large vertical bending load is produced on the spindle leading to fracture failure
Solution Approach 1:
The ground reference roller is repositioned to a lateral offset position beside the spindle rather than longitudinally aft. This dimensional change in positioning eliminates the long moment arm that caused excessive bending loads, while the articulated linkage mechanism provides the ground-following capability in a different geometric configuration that protects the spindle.
Solution Approach 2:
An articulated linkage mechanism serves as an intermediary between the ground reference roller and the cutting blade assembly. This intermediary transmits the ground contour information while isolating the spindle from large bending loads, allowing ground-following motion without compromising spindle reliability.
3Device complexity
If the cutting head and conveyor are rigidly connected, then the structure is simpler, but it is difficult to lift the head high enough for easy service and maneuvering
Solution Approach 1:
The cutting head assembly is made dynamically movable relative to the conveyor through articulated linkages and hydraulic lifting mechanisms. This dynamic connection allows the cutting head to be raised to various positions for service and maneuvering, while the linkage structure maintains the necessary mechanical relationships during operation.
4Productivity
If the conveyor is positioned low to capture the slab, then the slab capture is effective, but the conveyor drags on the ground during maneuvering and transport
Solution Approach 1:
The conveyor position is made dynamically adjustable through the articulated linkage system and hydraulic mechanisms. During harvesting operation, the conveyor is positioned low to effectively capture slabs from the cutting blade. During maneuvering and transport, the entire cutting head assembly can be raised, lifting the conveyor clear of the ground to prevent dragging and damage.
Data Source
AI summary
An articulated cutting head and conveyor mount for sod harvesting machines. The invention provides a linkage design that can provide many benefits including: allowing the operator to see the cutting operation, enabling the high lifting of the cutting head for service and maneuvering, managing the vertical bending load of the ground reference roller, providing high transverse stiffness, maintaining the position of the conveyor relative to the cutting head. The linkage design can include fewer parts than previous designs while still being robust and durable. As such, cutting heads employing the linkage design of the present invention can produce higher quality slabs with less service and maintenance than when using current designs.