Mower Deck Raising Mechanism Using Four-Link Suspension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lawn mower deck height adjustment mechanisms are inefficient and unstable, leading to wagging of the mower deck during operation, affecting mowing flatness and potentially causing damage from uneven terrain.
Innovation Solution
A raising and lowering mechanism using a four-link frame system with a fine adjustment screw and rotatable axle, allowing for quick and stable height adjustment of the mower deck, with a handle-operated system that locks into position to maintain desired heights and prevent collision with obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a chain suspension system is used to hang the mower deck, then the structure is simple, but the mower deck waggles during operation and is unstable
Solution Approach 1:
The suspension system is divided into multiple independent four-link frames (front hanger and rear hanger), each consisting of four links connected by hinges. This segmentation allows each link to independently absorb shocks and maintain stability, preventing the overall deck from wagging while keeping the structure relatively simple.
Solution Approach 2:
The four-link frame system uses multiple hinges and rotating connections that allow dynamic adjustment and movement. The links can rotate and pivot as needed, enabling the suspension to adapt to terrain changes while maintaining deck stability. The system transitions from a rigid chain to a dynamic, multi-degree-of-freedom structure.
2Device complexity
If a conventional height adjustment mechanism is used, then the structure is simple, but the height adjustment efficiency is low
Solution Approach 1:
The height adjustment mechanism uses a dynamic four-link frame system where pushing or pulling the handle rotates the rotatable axle, which through a chain of mechanical connections (driving lever, fine adjustment screw, swing arm, bridging swing arm) quickly raises or lowers the mower deck. This dynamic mechanical advantage provides fast adjustment compared to conventional slow-adjustment mechanisms.
Solution Approach 2:
The adjustment mechanism is segmented into distinct functional components: the handle, rotatable axle, driving lever, fine adjustment screw, and swing arm. Each component performs a specific function in the adjustment sequence, allowing for quick and controlled height changes while maintaining structural simplicity.
3Device complexity
If the mower deck is fixed at a single height, then the structure is simple, but it cannot adapt to uneven terrain
Solution Approach 1:
The four-link frame suspension system provides dynamic height adjustment capability, allowing the mower deck to be raised or lowered in response to terrain conditions. The mechanism enables the deck to adapt to uneven ground by lifting over hillocks or lowering to avoid obstacles, improving terrain adaptability while maintaining a relatively simple overall structure.
Solution Approach 2:
The system allows change in the vertical position parameter of the mower deck through manual operation of the handle and rotatable axle mechanism. This parameter change enables the deck to adjust its height relative to the terrain, improving adaptability to various ground conditions without requiring a complex automated system.
4Ease of operation
If the mower deck can be easily lowered, then it can avoid collision with obstacles, but the height adjustment precision is reduced
Solution Approach 1:
The adjustment mechanism is segmented into components that provide both coarse and fine control: the handle and rotatable axle provide the primary lowering action, while the fine adjustment screw provides precise control over the final position. This segmentation allows for easy operation combined with height precision, as each component handles a specific aspect of the adjustment.
Solution Approach 2:
The mechanism uses dynamic mechanical connections that allow smooth, controlled adjustment. The rotating axle and linked arms provide a progressive motion that maintains precision during the adjustment process, enabling the user to easily lower the deck while still achieving precise height positioning through the fine adjustment screw.
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
Enables precise and stable height adjustment of the mower deck, preventing damage to the lawn and mechanical structure by allowing the deck to lift over uneven terrain, ensuring consistent mowing quality and reducing mechanical stress.
Implementation Method 1
an upper end of the driving lever being in screw connection with a fine adjustment screw
Implementation Method 2
One end of the rotatable axle is fixedly connected with a driving lever
Implementation Method 3
the driving lever to rotate in the clockwise direction, then the end of the fine adjustment screw opposite a head thereof pushes the upper end of the swing arm
Implementation Method 4
a front end of the front hanger and a front end of the rear hanger being hinged, independently, to the frame of the lawn mower
Implementation Method 5
the front hanger and the rear hanger are, independently, a four link frame
Data Source
AI summary
A mower deck suspended stably from a lawn mower frame by a four link frame of a front hanger and four link frame of a rear hanger. The height of the mower is adjusted when a handle is pushed forward to rotate a rotatable axle in a clockwise direction, which causes a driving lever to rotate in a clockwise direction. A fine adjustment screw pushes a swing arm to rotate rearward, which forces a bridging swing arm to rotate in a clockwise direction via a second link. The bridging swing arm forces the first link to swing upward which forces the rear end of the rear hanger to swing upward, thereby raising the mower deck. When the handle is pulled rearward, the mower deck will be lowered.