Tractor Three-Point Link Mechanism with Interlocking Swing Arm
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Solution Overview
Problem
The existing three-point link mechanism in tractors does not improve operation sensitivity unless the tow load reaches a predetermined amount, limiting the ability to lift and lower work apparatuses with high sensitivity in response to varying loads.
Innovation Solution
The tractor incorporates a three-point link mechanism with an interlocking swing arm that swings in conjunction with the load receiver, allowing the contact position of the load receiver and interlocking swing arm to be changed, thereby amplifying the swing of the load receiver and enhancing operation sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the interlocking swing arm is designed to swing only when the load receiver swings by a predetermined amount or more, then the three-point link mechanism is simpler to control, but the operation sensitivity is insufficient for small tow loads
Solution Approach 1:
The interlocking swing arm is designed to dynamically change its state between locked and unlocked positions. The locking member can lock the swing arm at a specific position to prevent swinging for small loads, while releasing to allow swinging for larger loads. This dynamic state change enables the system to adapt its sensitivity based on the applied load, resolving the contradiction between control simplicity and operation sensitivity.
Solution Approach 2:
The system changes the operational parameter of the interlocking swing arm from a fixed state to a variable state. By using the locking member to control whether the swing arm can swing, the system effectively changes the parameter of swing availability. This allows the mechanism to have different operational characteristics (locked/unlocked) based on the load conditions, improving sensitivity for specific load ranges while maintaining simplicity overall.
2Device complexity
If the contact position of the load receiver and interlocking swing arm is fixed, then the link mechanism structure is simpler, but the ability to amplify swing amount is limited
Solution Approach 1:
The contact position between the load receiver and interlocking swing arm is made dynamic rather than fixed. The swing arm can pivot at different positions along its length depending on the load conditions, allowing the mechanical advantage and swing amplification to vary. This dynamic position adjustment enables greater swing amplification capability without significantly complicating the overall structure.
Solution Approach 2:
The interlocking swing arm is designed with multiple potential contact points or a distributed contact surface that can engage at different positions. This segmentation of the contact interface allows the system to effectively have multiple lever arm lengths, providing variable swing amplification. The load receiver can press against different portions of the swing arm, creating different mechanical advantage ratios as needed.
Data Source
AI summary
A tractor includes a three-point link mechanism to which a work apparatus is to be attached so as to be able to move upward and downward, a hydraulic drive to perform a swing operation to swing the three-point link mechanism, a load receiver to swing in response to a tow load being applied from the work apparatus when the work apparatus performs ground work while being towed by the vehicle body, and a link mechanism to transmit an amount of operation for the swing operation to the hydraulic drive according to an amount of swing of the load receiver. The link mechanism includes, at a most upstream position, an interlocking swing arm to swing in conjunction with the swing of the load receiver about a swing axis that is different from a swing axis of the load receiver, the load receiver includes a first portion to press the interlocking swing arm that includes a second portion contactable with the first portion so to be pressed by the first portion, and a contact position of the first and second portions.