Wrench Driving Surface Notches for Rounding Fasteners
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Solution Overview
Problem
Conventional hand tools for driving fasteners often round off the corners of fastener heads due to mismatched driving surfaces, leading to marring and sharp edges, which can cause injury when the fastener is removed.
Innovation Solution
A wrench design featuring driving surfaces with a contacting area and two yielding areas, including a contact portion and notches, that matches the sides of normal fasteners and effectively bites rounded fasteners, preventing corner damage and marring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional driving surfaces are used, then the structure is simple, but the corners of fastener heads are rounded off and marring occurs
Solution Approach 1:
The driving surface is segmented into multiple functional zones: a contacting area with a contact portion for normal engagement, notches for biting into rounded fasteners, and yielding areas for deformation. This segmentation allows each zone to perform its specific function, preventing corner rounding while maintaining structural simplicity
Solution Approach 2:
Different regions of the driving surface are given different geometric properties tailored to their function: the contact portion has a flat surface for normal fasteners, while the notches have sharp edges for biting into rounded fasteners. This local differentiation resolves the contradiction by providing precise corner protection only where needed
2Manufacturing precision
If special designed wrenches with rounded ridges are used, then fastener head corners are protected from marring, but assistance tools are required to hold rounded fasteners
Solution Approach 1:
The wrench design merges multiple functions into a single tool: the contacting area provides protection for normal fasteners, while the notches provide biting capability for rounded fasteners. This combination eliminates the need for assistance tools while maintaining corner integrity, resolving the contradiction between precision and operational independence
3Adaptability or versatility
If driving surfaces with notches are used, then rounded fasteners can be bitten effectively, but the structure becomes more complex
Solution Approach 1:
The driving surface is divided into discrete notches within the contacting area, creating a segmented structure that provides biting edges for rounded fasteners. This segmentation achieves versatile engagement capability while keeping the overall structure relatively simple through localized features
Solution Approach 2:
The notched driving surface design provides universal functionality by accommodating both normal fasteners (through the contact portion) and rounded fasteners (through the notches). This multi-functionality increases adaptability without requiring multiple separate tools or overly complex configurations
Data Source
AI summary
A wrench includes a handle and an open-end with two jaws and each jaw has a driving surface. Each driving surface has a contacting area and two yielding areas. The contacting area is located between the two yielding areas and includes a contact portion and two notches. The contact portion is located between the two notches, and two extension areas each are connected between the yielding area and the notch corresponding thereto. A corner is formed at a joint area of the contact portion and an inside of the notch so as to bite a rounded fastener head. The contact portions are matched with straight sides of a normal fastener head.