Ratchet Mechanism for Rotary Mower Cutting Unit Positioning
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Solution Overview
Problem
Conventional rotary mowers with three-point suspension systems face challenges in securely transitioning the cutting unit between transport and operating modes, often relying on complex hydraulic and mechanical systems that are not always reliable or compact.
Innovation Solution
A central suspension system for the cutting unit utilizing a ratchet mechanism with three cooperating ratchets, where the upper ratchet is limited by a spring and the lower ratchet has a handle and pins for rotation limitation, ensuring secure positioning during transport and operation, and allowing for easy switching between modes using a cord mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic cylinder with mechanical blocks is used to secure the mowing unit, then the cutting unit can be positioned correctly for transport, but the system becomes complex and less reliable
Solution Approach 1:
The patent replaces the complex hydraulic-mechanical blocking system with a pure mechanical ratchet mechanism. The ratchet teeth engage with pawls to provide automatic mechanical locking in transport and working positions, eliminating the need for hydraulic blocks and simplifying the overall system while improving reliability through passive mechanical engagement.
Solution Approach 2:
The ratchet mechanism provides automatic self-locking functionality. When the cutting unit is raised or lowered, the ratchet teeth automatically engage with the corresponding pawls at specific positions, providing self-service positioning without requiring active hydraulic control or manual intervention for locking, thereby reducing system complexity.
2Ease of operation
If a cord-operated lock release mechanism is used, then mode changing is simplified, but the positioning reliability during transport may be compromised
Solution Approach 1:
The cord mechanism serves as an intermediary that actuates the ratchet pawl to disengage from the teeth. Pulling the cord rotates the pawl carrier, causing the pawl to withdraw from the engaged ratchet tooth, thereby releasing the lock. This provides easy operation while the robust ratchet teeth-pawl engagement ensures positioning reliability during transport.
Solution Approach 2:
The locking mechanism is segmented into distinct functional components: the ratchet teeth on the oscillating arm, the pawl on the fixed arm, and the cord-operated pawl carrier. This segmentation allows the cord to specifically control pawl engagement/disengagement while the ratchet teeth provide the primary positioning structure, maintaining both ease of operation and reliability.
3Volume of moving object
If a compact locking mechanism is implemented, then the system size is reduced, but the ability to maintain equal pressure distribution may be affected
Solution Approach 1:
The ratchet mechanism utilizes angular/rotational dimension for locking. The pawl carrier rotates about a fixed axis to engage or disengage the pawl from the ratchet teeth. This rotational degree of freedom provides compact locking action in a small space while the oscillating arm's angular position (controlled by hydraulic cylinder) maintains the cutting unit's height and pressure distribution independently.
Solution Approach 2:
The system separates the locking function (ratchet-pawl mechanism) from the positioning function (hydraulic cylinder controlling oscillating arm angle). The compact ratchet mechanism handles only the locking task, while the hydraulic system maintains pressure distribution through controlled oscillation angle, allowing both requirements to be satisfied simultaneously.
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 ratchet mechanism provides a simple, compact, and reliable method to maintain the cutting unit's correct position during transport and operation, ensuring equal pressure distribution and efficient mode transitions, enhancing the mower's operational reliability and ease of use.
Implementation Method 1
The upper ratchet is being pressed down by a spring 6 to the lower ratchet 10
Implementation Method 2
raising and lowering of the mowing unit is operated by a hydraulic cylinder
Implementation Method 3
the upper one works with the lower one by sliding over its teeth
Data Source
AI summary
The subject of the invention is a system of positioning the cutting unit of a rotary mower with a central suspension system. The positioning system of the rotary mower's cutting unit equipped with the central suspension system comprising a rotor arm (1) connected to the carrying arm to which the cutting unit (14) is attached. Said cutting unit (14) can be raised to the desired position by means of a hydraulic cylinder (15) and can be blocked by the locking mechanism controlled by cords (5), characterized in that the locking element is a ratchet mechanism located on the rotor arm (1). The ratchet mechanism includes three rotationally mounted ratchets (3, 10, 12), where the lower one (10) works with the upper one (3) by sliding over its teeth (3A) and (3B). The ratchet which is at the end of the carrying arm works with the other ratchets (3) and (10), depending on the positioning of the cutting unit (14).