Bolt Extractor With Distal End Cutting Edges
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Solution Overview
Problem
Existing bolt extractor devices face difficulties in engaging and removing damaged or stripped threaded fasteners, as the edges of the aperture or peripheral heads can become damaged further when attempting removal, making extraction challenging and often impossible.
Innovation Solution
The bolt extractor features a drive end with a shaft and an engagement end that includes side cutting edges and end cutting edges, providing multiple torque transfer areas, with the end cutting edges acting as a punch to guide the drill bit and enhance engagement with the threaded fastener, even if the head is stripped or broken off, allowing for improved torque application and hole drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bolt extractors with only fluted edges are used, then the device structure remains simple, but the torque transfer capability and extraction reliability are insufficient when dealing with damaged fasteners
Solution Approach 1:
The engagement end is segmented into multiple functional zones: fluted edges for initial engagement, side cutting edges for radial penetration and torque transfer, and end cutting edges for axial engagement. Each segment performs a specific function to collectively improve extraction reliability on damaged fasteners.
Solution Approach 2:
Different regions of the extractor engagement end have different geometries and functions: the fluted edges provide initial grip, the side cutting edges create engagement areas on the hole walls, and the end cutting edges engage the hole bottom. This local differentiation optimizes torque transfer at each location.
2Power
If multiple engagement areas are added to the extractor, then torque transfer capability is improved, but manufacturing complexity increases
Solution Approach 1:
The side and end cutting edges are designed to automatically create engagement areas during insertion into the drill hole. The cutting edges pre-form the necessary engagement surfaces on the hole walls and bottom, eliminating the need for separate engagement area creation steps and simplifying the overall process.
3Force
If the extractor is driven hard to remove damaged fasteners, then extraction force is sufficient, but the damaged head becomes worse and extraction becomes impossible
Solution Approach 1:
The side and end cutting edges act as intermediaries that distribute extraction forces across multiple engagement areas (hole walls and bottom) rather than concentrating stress at a single point. This distributes the load and prevents further damage to the already compromised fastener head.
4Manufacturing precision
If the drill hole is drilled without guidance, then drilling speed is fast, but hole accuracy and extractor engagement are poor
Solution Approach 1:
The end cutting edges at the distal end of the extractor serve as a preliminary guidance feature during drill hole creation. They help establish the correct hole trajectory and position before the main drilling operation, ensuring accurate hole placement without requiring separate centering steps.
Data Source
AI summary
A threaded fastener extractor (110 or 510) includes a drive end configured to interface with a powered driver where the drive end has a shaft, and an engagement end coupled to the drive end coaxial with the drive end about an axis. The engagement end is configured to engage with an extraction hole (330) formed in a threaded fastener (300). The engagement end includes side cutting edges (140 or 530) disposed on lateral sides of the engagement end and end cutting edges (150 or 540) disposed at a distal end of the engagement end. The side cutting edges (140 or 530) and the end cutting edges (150 or 540) each provides engagement areas for torque transfer between the extractor (110 or 510) and the threaded fastener (300).