Tractor Three-Point Coupling Automatic Upper Link Engagement
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Solution Overview
Problem
The existing three-point coupling systems for tractors and agricultural implements require operators to enter a confined space to attach the top link, which is uncomfortable and inefficient, especially when lower link connections are short and tire size is large, limiting access and increasing the difficulty of automatic coupling.
Innovation Solution
A support device with limited articulation on the attachment, featuring a rocker, coupler, and crank, guides the upper link's coupling jaw along a curved path from above, allowing automatic engagement with the top link connection point during reverse motion, and includes a tensioning device and actuator for secure locking and unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the lower links of the tractor are very short and the tires are large, then the payload capacity is improved, but the mounting space between the tractor and the attachment is limited, making operator access uncomfortable
Solution Approach 1:
The support device is pre-positioned on the attachment frame before coupling occurs. When the tractor reverses, the upper link is automatically guided into the connection point by the pre-positioned support device, eliminating the need for operator intervention in the confined space between short lower links and large tires.
Solution Approach 2:
The coupling system performs self-service through automatic coupling. The support device with limited articulation automatically guides the upper link into place during reverse motion, and the quick coupler locks automatically secure the connection, freeing the operator from manually accessing the confined mounting space.
2Device complexity
If manual control of threading the upper link into the upper link connection point is required, then the coupling mechanism is simple, but the operator must stand between the tractor and the attachment, which is uncomfortable and inefficient
Solution Approach 1:
The support device acts as an intermediary between the upper link and the attachment frame. It provides the necessary guidance and positioning function that manual threading would otherwise require, enabling automatic coupling while maintaining a relatively simple overall mechanism.
Solution Approach 2:
The support device incorporates a curved guide surface that directs the upper link along a specific path into the connection point. This curved geometry automatically aligns and seats the upper link during reverse motion, replacing manual threading operations with automatic geometric guidance.
3Ease of operation
If a separate three-point frame is used that must be unhooked and hooked into the lower and upper links, then the coupling can be performed from a distance, but the heavy frame (30-40 kg) must be manually handled, which is disadvantageous and uncomfortable
Solution Approach 1:
The coupling system is segmented into fixed components (support device mounted on attachment frame) and moving components (upper link with coupling jaw). This eliminates the need for a separate heavy three-point frame that must be manually handled, as the coupling functionality is integrated directly onto the attachment.
Solution Approach 2:
The support device with limited articulation performs the positioning and guidance functions automatically during reverse motion, eliminating the need for manual handling of heavy frames. The system serves itself by using the reverse motion of the tractor to automatically engage the coupling.
4Adaptability or versatility
If the upper link movement is derived from the lower link movement with standardized coupling points, then the system allows tolerances, but the upper link does not find the upper link connection point, so the system has not been introduced in practice
Solution Approach 1:
The support device incorporates a curved guide surface that actively guides the upper link along a specific trajectory into the connection point. This curved geometry compensates for tolerance variations in standardized coupling points, ensuring positive engagement regardless of minor dimensional variations.
Solution Approach 2:
The limited articulation of the support device provides continuous geometric feedback during the coupling process. As the upper link moves toward the connection point, the curved guide surface automatically adjusts the alignment, providing real-time correction for tolerance variations and ensuring accurate final positioning.
Data Source
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AI summary
The three-point coupling device has two lower links (3) arranged at a tractor (1) or are spaced horizontally, where each lower link has a catcher (5) and a higher and centrally located upper link (4) with coupling catcher (7) for an agricultural attachment (9). The device has lower connecting points for the lower links and an upper link connection (14) for the upper link. The catcher of the upper link and the catcher of the two lower links are coupled in the coupling position by quick coupling locking device to the connection points.