Cam-Driven Low Profile Sickle Drive Mechanism
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Solution Overview
Problem
Existing agricultural cutting machines, such as combines and windrowers, face challenges with side-mounted sickle drives that cause interference with plant material flow, require significant structural support, and generate vibrations leading to fatigue and increased complexity.
Innovation Solution
A low-profile cam-driven sickle drive mechanism is integrated into or below the header floor, featuring a flat enclosure with pivot arms and cam elements that allow unhindered plant material flow and cancel opposing forces, reducing the need for extensive structural support and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If side-mounted sickle drives are used, then the knife assembly can be driven reciprocatingly, but the header requires significant frame structure to support the drive and withstand forces and vibrations
Solution Approach 1:
The patent repositions the sickle drive from a side-mounted horizontal configuration to a centrally-located vertical configuration. The cam drive mechanism is oriented with its rotation axis vertical, allowing the cam lobes to drive the knife assembly reciprocatingly in a vertical plane rather than horizontal. This dimensional change allows the drive to be integrated into the header floor structure, eliminating the need for significant side-mounted frame support structures while maintaining the reciprocating drive capability.
2Power
If side-mounted drives are used, then the knife assembly can be driven, but the end structure or crop divider must be relatively wide to accommodate the drive and direct adjacent standing crops
Solution Approach 1:
The patent relocates the drive mechanism from the horizontal side-mounted position to a vertical central position within the header floor. By orienting the cam drive with a vertical rotation axis and positioning it within the header floor structure, the patent eliminates the need for wide end structures to accommodate side-mounted drives. The crop divider can be made narrower since the drive is no longer positioned at the header ends, improving maneuverability and reducing crop damage while maintaining effective knife assembly operation.
3Stability of the object's composition
If two drives are located on opposite sides of the header to cancel forces and vibrations, then the forces can be balanced, but long mechanical drive lines are required which add weight, cost and complexity
Solution Approach 1:
The patent merges the functions of two separate side-mounted drives into a single centrally-located cam drive mechanism. The single cam drive with vertically oriented lobes can simultaneously drive multiple knife assemblies or a single long knife assembly, eliminating the need for separate drives on opposite sides and the long mechanical drive lines that would connect them. This consolidation maintains force balance and vibration cancellation capabilities while significantly reducing mechanical complexity, weight, and cost.
4Ease of operation
If the drive is located at the side of the header, then clearances for removal of the knife assembly are provided, but the drive interferes with plant material flow and requires significant structural support
Solution Approach 1:
The patent repositions the drive mechanism from a side-mounted location that protrudes into the plant material flow path to a central location integrated within the header floor structure. By orienting the cam drive vertically and positioning it within the floor, the drive no longer interferes with the horizontal flow of plant material over the header. Knife assembly removal clearance is maintained through appropriate design of the vertical drive mechanism and surrounding structure, eliminating flow interference while preserving maintenance accessibility.
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
This configuration reduces vibration, fatigue, and structural stress while maintaining efficient plant material flow and reducing the header's overall width, making the machine more maneuverable and less likely to accidentally push down adjacent crops.
Implementation Method 1
a first cam element supported in the cavity in connection with the first input element for rotation thereby. The first cam element includes a radial facing cam surface extending about the first rotational axis which varies in radial distance therefrom. A first pivot arm has a first end and an opposite upwardly extending second end configured for connection to a knife assembly of a sickle located forwardly thereof. A first pivot shaft supports the first pivot arm for sideward pivotal movement about an upstanding first pivotal axis, and the first end of the first pivot arm includes a cam follower configured and positioned in following relation to the first cam element such that rotation of the first cam element about the first rotational axis will move the first end radially relative to the first rotational axis to reciprocatingly pivot the first pivot arm sidewardly.
Data Source
AI summary
The drive has an input rotatable about an upstanding rotational axis and carries a cam followed by a pivot arm pivotable about an upstanding pivotal axis. A power source is connected in rotatably driving relation to the input. The pivot arm connects to a knife assembly of a sickle. The input, cam and pivot arm are generally flat, and the power source is vertically coextensive therewith for incorporation in or below the floor of a header of a plant cutting machine. Rotation of the input causes offset movement of the cam about the rotational axis, resulting in sideward pivoting of the pivot arm and sickle knife. A second cam drive can oppositely drive a second sickle knife, such that opposite forces generated by operation of the drives will be largely canceled.