Lawn Mower Housing Front Wall as Integrated Lifting Handle
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Solution Overview
Problem
Walk-behind lawn mowers require additional handles for lifting, increasing component count and cost, as their existing housings are not designed to serve as effective handles due to insufficient strength and rigidity.
Innovation Solution
The housing of the lawn mower incorporates a front wall portion with a thickness more than twice that of other parts, featuring a downwardly convex bottom surface that functions as a handle, allowing for efficient lifting without additional components, and includes reinforcing ribs and a curved outer surface to guide rainwater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate handle is added to the housing for lifting the lawn mower, then the lifting function is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the housing structure with the lifting handle function by making the front wall portion of the housing serve dual purposes: structural coverage and lifting handle. The front wall portion is designed with increased thickness (more than twice the thickness of other housing portions) and a downwardly convex bottom surface, allowing it to function as an integrated lifting handle without requiring separate handle components.
Solution Approach 2:
The front wall portion of the housing is designed to perform multiple functions simultaneously: it covers the front part of the cutter, provides structural support, and serves as a lifting handle. This multi-functional design eliminates the need for separate dedicated handle components, reducing overall device complexity while maintaining lifting capability.
2Strength
If the housing is designed with sufficient strength and rigidity to serve as a frame, then the structural integrity is improved, but the front end portions cannot effectively serve as lifting handles
Solution Approach 1:
The patent applies local quality by varying the thickness of different housing portions. The front wall portion is designed with a thickness more than twice that of other housing portions, concentrating additional material and strength specifically where lifting capability is needed, while maintaining standard thickness elsewhere to preserve overall structural integrity without unnecessary weight increase.
Solution Approach 2:
The patent changes the physical parameters of the front wall portion by increasing its thickness significantly (more than twice the thickness of other portions) and modifying its surface geometry (downwardly convex bottom surface). These parameter changes enhance the front wall's ability to function as a lifting handle while maintaining the housing's overall structural strength.
3Ease of operation
If the front wall portion is made thicker to serve as a handle, then the lifting comfort is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the front wall portion into an inner wall, an outer wall, and intermediate ribs. This segmentation allows the thick front wall to be molded without sink marks by creating a structured internal framework that supports the material during cooling, while still achieving the desired external thickness for comfortable lifting.
Solution Approach 2:
The patent employs curvature by designing the bottom surface of the front wall portion as downwardly convex. This curved geometry serves multiple purposes: it provides ergonomic contact surfaces for hands during lifting, increases the surface area for load distribution, and facilitates proper material flow and cooling during the molding process, thereby improving manufacturability.
Data Source
AI summary
A walk-behind lawn mower includes a cutter and a housing covering the cutter for allowing rotation of the cutter to cut grass. The housing includes a front wall portion covering a front part of the cutter and a portion other than the front wall portion. The front wall portion extends laterally of the housing. The front wall portion has a thickness more than twice a thickness of the portion other than the front wall portion. The front wall portion has a downwardly convex bottom surface, and serves as a handle for use in lifting up the lawn mower.