Variable Speed Plunger for Agricultural Baler Compression
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Solution Overview
Problem
Large square balers with fixed length connecting rods cannot vary the plunger movement and speed relative to the crank arm speed, resulting in uniform compression speed and dwell time for each stroke, which may not optimize crop densification and bale formation.
Innovation Solution
Incorporating a variable length connecting link or crank arm that can change length during operation to independently control the plunger speed, allowing for varying compression rates and dwell times based on sensed modes and phases, enabling the plunger to move at different speeds than the crank arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed length connecting rod is used, then the structure is simple and reliable, but the plunger speed cannot be varied relative to the crank arm speed
Solution Approach 1:
The connecting rod structure is transformed from a fixed length to a variable length mechanism. The patent employs a telescopic connecting rod with extendable and retractable segments, allowing the length to change dynamically during the compression cycle. This enables the plunger speed to be independently controlled from the crank arm speed, resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
The connecting rod length is changed as a controllable parameter during operation. By adjusting the extended or retracted state of the telescopic segments, the effective length of the connecting rod varies, which directly alters the plunger's motion characteristics and speed relative to the crank arm, achieving versatile speed control.
2Manufacturing precision
If the plunger compresses crop at uniform speed, then the mechanism is simple, but crop densification is not optimized
Solution Approach 1:
The compression process is divided into periodic phases with different speed characteristics. The variable length connecting rod enables the plunger to move at different speeds during different portions of the compression cycle - faster during initial compression and slower during final densification - optimizing crop packing without requiring complex continuous control systems.
Solution Approach 2:
The compression speed is made dynamic rather than uniform. The telescopic connecting rod allows the plunger acceleration and deceleration at specific points in the cycle, creating variable speed compression that optimizes densification by applying force more effectively during critical compression phases.
3Ease of operation
If the plunger dwell time at extended position is fixed, then the mechanism is simple, but bale formation during binding is not optimized
Solution Approach 1:
The dwell time at the extended position is made variable through the telescopic connecting rod mechanism. By controlling the extension or retraction of the connecting rod segments while the plunger is at its forward position, the system can hold the plunger stationary for extended periods during binding operations, improving bale formation without requiring a separate dwell time control mechanism.
Data Source
AI summary
An agricultural harvesting machine for crop material including a crank arm connected to a rotational power source, a plunger having an extended position which is located further rearward in a compression chamber than a retracted position, and a connecting link connected between the plunger and the crank arm. One of the connecting link and the crank arm has a variable length. The plunger moves between the retracted and extended positions during a run mode as the crank arm rotates. The plunger changes speeds during an event phase based upon one of the connecting link and the crank arm varying lengths.