Lawnmower Rear Shield with Thin-Walled Part for Bending Control
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Solution Overview
Problem
Walk-behind lawnmowers face issues with debris projection and rear shield bending, which can cause the shield to catch on structural components, increasing resistance and wear, and existing solutions either compromise durability or increase component complexity.
Innovation Solution
A rear shield with a thin-walled part at its central heightwise direction, allowing controlled bending and minimizing contact with other components, and a protruding part to catch on grass or objects, reducing resistance and preventing catching on structural parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the bending rigidity of the rear shield is increased to minimize bending, then the bending of the rear shield is reduced, but the flexibility of the rear shield decreases and resistance to movement increases when changing direction
Solution Approach 1:
The rear shield employs non-uniform thickness distribution, with a thin-walled part at the central heightwise location and thicker parts at the upper and lower ends. This local quality variation allows the thin-walled central part to bend easily during direction changes, reducing movement resistance, while the thicker end parts maintain overall structural stability and durability.
2Stability of the object's composition
If the bending rigidity of the rear shield is increased to minimize bending, then the bending of the rear shield is reduced, but the durability to wear and breakage decreases
Solution Approach 1:
The rear shield employs non-uniform thickness distribution, with a thin-walled part at the central heightwise location and thicker parts at the upper and lower ends. This local quality variation allows the thin-walled central part to bend easily during direction changes, reducing movement resistance, while the thicker end parts maintain overall structural stability and durability.
3Stability of the object's composition
If a separate minimizing member is provided to minimize bending of the rear shield, then the bending is minimized, but the number of components increases
Solution Approach 1:
The bending control function is merged into the rear shield structure itself through the thin-walled part design. The varying thickness distribution within the single shield structure provides the desired bending characteristics without requiring separate minimizing members, thus reducing component count while achieving the same functional effect.
4Device complexity
If the rear shield is made with uniform thickness to maintain simplicity, then the structure is simple, but the rear shield may catch on axles or other structural components when bending occurs
Solution Approach 1:
The rear shield employs non-uniform thickness distribution, with a thin-walled part at the central heightwise location and thicker parts at the upper and lower ends. This local quality variation allows the thin-walled central part to bend easily during direction changes, reducing movement resistance, while the thicker end parts maintain overall structural stability and durability.
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 effectively restricts rear shield bending to prevent catching on other components, reduces resistance during operation, and maintains durability without increasing component complexity, ensuring smooth movement and reduced wear.
Implementation Method 1
a rear shield in the form of an elastic sheet extending downwardly from a rear end part of the housing, wherein the elastic sheet has a thin-walled part formed at a central part in a heightwise direction
Data Source
AI summary
The rear shield of a walk-behind lawnmower extends downward from a rear end part of a housing and is in the form of an elastic sheet. The sheet has a thin-walled part formed in a central site in a heightwise direction between an upper end part and a lower end part, the upper end part being attached to the rear end part of the housing. The thin-walled part has a thickness set to be smaller than a thickness of other parts.