Agricultural Pickup Caster Wheel Spring Biasing Mechanism
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Solution Overview
Problem
Agricultural machine pickups face issues with caster wheels projecting beyond permissible widths during transportation and experiencing uncontrollable oscillation when not in contact with the ground, leading to stability and steering problems.
Innovation Solution
The use of support wheels mounted on carriers that rotate about a horizontal axis, connected to the pickup frame via springs, which bias the wheels into a predetermined position when raised, preventing sideways projection and absorbing oscillations to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If caster wheels are used for support, then the pickup can be easily steered and the wheels automatically align with the direction of travel, but the wheels project laterally beyond the sides of the pickup when raised off the ground during transportation
Solution Approach 1:
The wheel carrier is made dynamically adjustable between two states: during operation, the carrier allows the wheel to pivot freely on the caster axis for automatic alignment and steering; during transportation, the carrier is positioned to constrain the wheel laterally, preventing it from projecting beyond the pickup width. This dynamic reconfiguration resolves the contradiction between steering capability and transportation width compliance.
2Device complexity
If caster wheels are provided only for support and not used for steering, then they can be designed as simple caster wheels, but they rotate freely and move to positions that increase the width of the pickup beyond legally permissible limits
Solution Approach 1:
The carrier acts as an intermediary component between the wheel and the pickup frame. It provides a lateral constraint mechanism that limits the wheel's rotation range during transportation, preventing excessive width expansion while maintaining the simple caster wheel design for support functions.
3Speed
If the support wheels are raised off the ground during transportation, then the pickup can be moved, but the wheels can oscillate uncontrollably when not in contact with the ground
Solution Approach 1:
The carrier is designed with a lateral constraint mechanism that preemptively counteracts the oscillatory motion of the wheel when raised off the ground. By providing this preliminary anti-action through physical constraint, the system prevents uncontrolled oscillation before it can develop, maintaining stability during transportation at various speeds.
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 solution ensures the pickup remains within legal transportation widths and prevents uncontrolled oscillation, enhancing operator safety and stability by aligning wheels for straight travel and damping shocks.
Implementation Method 1
each carrier is connected by a respective spring to a point fixed relative to the frame of the pickup, the spring biasing the carrier to cause the support wheel to be oriented in a predetermined direction relative to the frame of the pickup
Implementation Method 2
a caster wheel is pivotable about a generally vertical axis, generally known as and herein referred to as a caster axis, but the point of contact of the wheel with the ground is offset from the caster axis. As a result, drag rotates the wheel such that its point of contact with the ground always lines up behind the caster axis in the direction of travel
Data Source
Figure 1~3
AI summary
A pickup is disclosed for an agricultural machine having a frame carrying a crop pickup mechanism and supported on the ground by means of two support wheels (14). Each support wheel (14) is rotatably mounted on a carrier (22) that is connected to the frame of the pickup for rotation about a caster axis (26). Each wheel carrier (22) is connected by a respective spring (32,132) to a point fixed (34) relative to the frame of the pickup. The spring (32,132) biases the carrier (22) to cause the support wheel (14) to park in a predetermined direction relative to the frame of the pickup.