Self-Leveling Rear Hitch Linkage for Implement Height Control
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Solution Overview
Problem
Conventional rear hitches on agricultural implements change height with the implement's vertical movement, leading to non-optimal angles during transport, increased forces on the hitch and implement, and interference with soil and trash flow, as well as limitations in tool placement.
Innovation Solution
A self-leveling rear hitch system using a pivotal link structure connected to the main depth control rockshaft maintains a constant hitch height through a lever arm and link system, distributing towing forces and minimizing interference with soil and trash flow, while reducing cost, complexity, and weight by positioning the hitch near the lift rockshaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rear hitch is rigidly mounted on the implement frame, then the structure is simple and strong, but the hitch height changes with implement vertical movement causing non-optimal angles during transport and increased forces on the hitch
Solution Approach 1:
The patent applies a dynamic hitch structure that automatically adjusts the hitch angle as the implement moves between raised and lowered positions. The hitch frame is connected via a linkage mechanism to the depth control rockshaft, allowing the hitch to pivot and maintain an optimal angle throughout the range of motion, resolving the contradiction between structural simplicity and operational ease.
2Ease of operation
If structures are used to maintain trailing hitch height with implement raising and lowering, then hitch height is maintained, but soil and trash flow is interfered with and tool placement is limited
Solution Approach 1:
The patent positions the hitch frame and linkage mechanism in a specific location on the implement frame, away from the centerline, to maintain hitch height while minimizing interference with soil and trash flow. This localized placement allows tools to be mounted in various positions without conflict, resolving the contradiction between height maintenance and adaptability.
3Strength
If hitch beams extend to the forward extremity of the main frame, then hitch strength is improved, but cost, complexity and weight increase
Solution Approach 1:
The patent extracts the essential function of the hitch beam from extending to the forward extremity of the main frame. Instead, the hitch frame is connected directly to the depth control rockshaft via a simplified linkage mechanism, maintaining sufficient strength while eliminating unnecessary complexity and weight, thus resolving the contradiction.
4Strength
If the hitch is positioned farther forward on the main frame, then hitch strength is improved, but interference with soil and trash flow increases
Solution Approach 1:
The patent positions the hitch frame in a rearward location on the implement frame, utilizing the rear dimension to avoid interference with soil and trash flow. This rearward positioning maintains sufficient hitch strength through proper linkage to the depth control rockshaft while eliminating the harmful interference effect, resolving the contradiction.
Data Source
AI summary
Implement hitch height control structure to maintain a rear hitch point at a generally constant height as the implement is raised and lowered. In one embodiment, a rectangular hitch frame is pivotally connected at a forwardmost end to lever arms on the implement lift rockshaft. Linkage structure connected between the hitch frame and the implement frame help control hitch frame attitude, rear hitch point height and force transfer to the implement frame. The hitch frame is located substantially behind the implement rockshaft for minimal interference with tool placement on the frame and limited interference with trash and soil flow under the main frame. In another embodiment, linkage structure includes a second rockshaft connected generally above the aft end of the main frame.