Handheld Tool Housing Stiffening Bracket Design
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Solution Overview
Problem
Hand-held tools, such as lawnmowers, often suffer from insufficient rigidity, particularly in plastic housings, when force is applied in the rear region, leading to instability and potential tipping during use.
Innovation Solution
A hand-held tool design featuring a handlebar with a mounting bracket fixed to the housing and connected to a stiffening strut, which allows for a stable connection via a fastening console, incorporating a detachable folding device with elastic deformation to distribute force evenly across the housing, and utilizing a form-fitting connection between the handlebar and stiffening struts to enhance rigidity without additional fastening means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single-shell plastic housing is used, then the device achieves lightweight construction and simplified manufacturing, but the rigidity and stability become insufficient when force is applied in the rear region
Solution Approach 1:
The housing is segmented into a single-shell plastic construction with integrated stiffening struts that divide the structural support function. The mounting bracket is separately designed as a distinct component that interfaces with the housing, allowing the housing itself to remain lightweight while the bracket provides additional structural support where needed.
Solution Approach 2:
The mounting bracket is designed to extend over more than three quarters of the housing width and is positioned to distribute forces across the entire housing structure. The bracket's form-fitting connection to the housing provides localized reinforcement exactly where force is applied, rather than requiring the entire housing to be heavily reinforced.
2Stability of the object's composition
If additional fastening means are added to connect the handlebar to the housing, then the connection stability improves, but the device complexity increases
Solution Approach 1:
The mounting bracket integrates multiple functions into a single component: it serves as both the structural connector between the handlebar and housing, and as the stiffening element itself. The bracket's design combines the fastening function with the structural support function, eliminating the need for separate fastening means.
Solution Approach 2:
The mounting bracket is designed with self-aligning features including form-fitting connections and elastic deformation capabilities that allow the bracket to automatically adjust and secure the handlebar without requiring additional fastening operations. The bracket's inherent elasticity provides self-adjusting clamping force.
3Strength
If the guide tube is rigidly fixed to the mounting bracket, then the connection strength improves, but the ability to fold for transport is lost
Solution Approach 1:
The connection between the guide tube and mounting bracket is designed as a dynamic, movable joint rather than a fixed rigid connection. The bracket's elastic deformation capability allows the connection to be rigid during operation (providing strength) while permitting folding motion during transport. The connection transitions between static and dynamic states based on operational requirements.
Solution Approach 2:
The connection parameters (rigidity, flexibility) are changed based on operational state. During normal operation, the elastic deformation is minimized providing a rigid strong connection. During transport/folding, the elastic properties are utilized to allow the guide tube to be folded down while maintaining connection integrity.
4Stability of the object's composition
If the mounting bracket extends over the entire housing width, then the force distribution improves, but the manufacturing complexity and material usage increase
Solution Approach 1:
The mounting bracket extends over more than three quarters of the housing width, providing sufficient force distribution without requiring complete full-width coverage. This partial extension achieves the necessary structural support and force distribution while reducing material usage and manufacturing complexity compared to a full-width bracket.
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 design provides improved stability and force distribution, allowing for a lightweight, single-shell plastic housing construction while maintaining structural integrity, even when the grass catcher box is full, and enables easy transportation by folding the handlebar.
Implementation Method 1
In order to compensate for tolerances and to avoid a static overdetermination of the clamping connection, provision is made for the fastening bracket and/or the guide tube to be elastically deformed when the folding device is in the clamped position. The elastic deformation is made possible by appropriate design and by the inherent elasticity of the material.
Data Source
Figure 1~2
Figure 3~6
Figure 7~9
AI summary
The hand-operated equipment has housing (2) on which several wheels (4) are mounted. A fixed handle link (5) is provided for guiding the working apparatus on the ground. The handle link is arranged along the direction (57) of travel in the rear portion (56) of housing. A guide tube (7) is extended from the rear portion of housing to the front portion (55) of housing. A cross brace (53) is provided in the handle link.