Drawbar Pin Ejector Mechanism for Stuck Implement Coupling
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Solution Overview
Problem
Drawbar pins often become stuck in their housings, making it difficult to attach or detach drawbar-pulled implements from tractors, necessitating a system that facilitates easier removal.
Innovation Solution
A drawbar assembly with a locking plate and ejector mechanism, featuring a pivotable handle with angled lever arms, allows partial ejection of the drawbar pin from the clevis bore, enabling easier removal by shifting the fulcrum points to progressively dislodge the pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drawbar pin is used to couple the drawbar and tongue together, then the implement can be securely attached to the vehicle, but the pin becomes stuck and difficult to remove from the housing
Solution Approach 1:
The ejector mechanism extracts the pin from its housing by applying force through the lever arm system. The handle with lever arm is designed to engage the pin and progressively eject it from the clevis bore, separating the pin removal function from the secure attachment function.
Solution Approach 2:
The locking plate is made movable between a locked position (where it obstructs the bore to secure the pin) and an unlocked position (where it allows pin removal). This dynamic element resolves the contradiction by allowing the system to switch between secure attachment and easy removal states.
2Stability of the object's composition
If the drawbar pin is fully retained in the housing, then the coupling is stable during operation, but additional force is required to initiate pin removal
Solution Approach 1:
The pin removal process is segmented into stages using the two-stage lever arm mechanism. The first arm segment handles initial pin dislodgement, the elbow provides a transition point, and the second arm segment completes the ejection. This segmentation reduces the peak force required by distributing the work across multiple mechanical advantage points.
Solution Approach 2:
The ejector mechanism combines the handle, lever arm with elbow, and locking plate into an integrated system. The lever arm merges the user's manual force with the mechanical advantage provided by the fulcrum points to achieve pin ejection with reduced effort.
3Reliability
If a locking mechanism is added to retain the pin, then the coupling reliability improves, but the device complexity increases
Solution Approach 1:
The locking plate serves multiple functions: it secures the pin in the locked position, guides the pin during ejection, and works with the ejector mechanism to enable controlled pin removal. The handle serves both as a manual operation interface and as part of the ejector mechanism, reducing the need for separate components.
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
The solution allows for efficient and easy removal of the drawbar pin from its housing, reducing the effort required for attachment and detachment of implements, enhancing operational efficiency in agricultural settings.
Implementation Method 1
the lever arm is pivoted so that the first arm segment contacts a first support such that the first support acts as a fulcrum for the lever arm and as the drawbar pin is urged out of the bores
Implementation Method 2
the contact point between the lever arm and the first support shifts from the first arm segment, through the elbow and then to the second arm segment
Data Source
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AI summary
A drawbar assembly for coupling a drawbar to a tongue of a towed implement includes a drawbar pin and a drawbar clevis having a bore configured to receive the drawbar pin. A locking plate is coupled to the drawbar clevis and movable between a pin-locked position in which the locking plate is configured to obstruct at least a portion of the bore, and a pin-unlock condition. An ejector mechanism is configured to dislodge the drawbar pin from the bore.