Adjustable Hitch Arm for Pull-Type Harvesters
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Solution Overview
Problem
Existing pull-type crop harvesting machines face challenges in accurately adjusting the hitch arm's position relative to the frame, leading to inefficient steering and potential damage due to significant forces applied during echelon movements, which can result in missed crop material or suboptimal header utilization.
Innovation Solution
A hydraulic cylinder system with adjustable stop members and ported ends to control the hitch arm's movement, allowing precise positioning and reducing impact forces by slowing the piston's movement as it reaches the end of its stroke, eliminating the need for heavy mechanical stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heavy mechanical stops are provided on the frame or hitch arm to locate the machine at the required echelon position, then the positioning function is achieved, but the mechanical elements must be built stronger to withstand significant impact forces during movement
Solution Approach 1:
The patent replaces heavy mechanical stops with a hydraulic cylinder system that uses hydraulic pressure to control and locate the hitch arm at the desired echelon position. The cylinder incorporates a cushioning mechanism with variable orifice flow control to manage the piston's approach to the end of its stroke, eliminating the need for rigid mechanical stops and reducing impact forces on mechanical components.
Solution Approach 2:
The hydraulic cylinder incorporates a cushioning mechanism with variable orifice flow control that slows the piston's movement before it reaches the end of its stroke. This beforehand cushioning reduces impact forces by controlling the rate at which hydraulic fluid is displaced during the final approach, preventing sudden mechanical shocks that would require stronger structural elements.
2Measurement precision
If the stop member is incorrectly positioned, then the header alignment is compromised causing missed crop material or suboptimal header utilization, but the operator can manually steer to compensate, this increases operator fatigue and causes more frequent returns to the end stop
Solution Approach 1:
The patent replaces manual steering operations with an automated hydraulic cylinder system that precisely positions the hitch arm at the correct echelon position. The variable orifice flow control mechanism automatically manages the piston's movement speed and positioning accuracy, eliminating the need for continuous manual steering adjustments and reducing operator fatigue while maintaining precise header alignment.
3Speed
If the hydraulic cylinder moves the piston quickly to the end of its stroke, then the echelon position is reached faster, but significant impact forces are applied to the mechanical elements
Solution Approach 1:
The hydraulic cylinder incorporates a cushioning mechanism with variable orifice flow control that slows the piston's movement before it reaches the end of its stroke. This beforehand cushioning reduces impact forces by controlling the rate at which hydraulic fluid is displaced during the final approach, preventing sudden mechanical shocks that would require stronger structural elements.
Solution Approach 2:
The patent employs variable orifice flow control that dynamically changes the flow resistance parameter as the piston approaches the end of its stroke. By varying the orifice opening size, the system maintains high speed during most of the piston's travel while automatically reducing speed near the endpoint, thus achieving both fast positioning and low impact forces.
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
Enables precise adjustment of the echelon position, reducing operator fatigue and machine damage while ensuring optimal header alignment and efficient crop harvesting by distributing forces more evenly and accurately.
Implementation Method 1
a hydraulic cylinder for actuating movement of the hitch arm relative to the frame between the first and second positions
Implementation Method 2
ported ends to control the hitch arm's movement, allowing precise positioning and reducing impact forces by slowing the piston's movement as it reaches the end of its stroke
Data Source
AI summary
A pull-type crop harvesting machine has a header carried on a frame mounted on ground wheels with a hitch arm extending from the frame over the header to a hitch coupling of a tractor. The hitch arm is mounted for pivotal movement about a generally upright axis such that in a first position the tractor tows the frame in echelon to one side and in a second position the tractor tows the frame in echelon. The movement is actuated by a hydraulic cylinder and stopped at one end of the movement by the piston with a rod coupling being adjustably mounted on the rod to adjust the end position. At the other end of the movement, the position is defined by a stop member mounted on the piston rod and adjustable relative thereto. Each end of the cylinder includes a cushion effect by using separate orifices for the fluid ports which slow fluid flow as the piston approaches the ends of the cylinder.