Magnetic Fastener Retainer with Alternating Pole Keeper
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Solution Overview
Problem
Existing magnetic devices for attracting and retaining fasteners are inefficient due to high lateral magnetic force, which causes slipping and magnetization of fasteners, leading to unreliable attraction and retention, and lack adjustability in fastener driving assemblies.
Innovation Solution
A magnetic device with a ring-shaped keeper and alternating pole magnets around the bit's proximate end, providing axial magnetic force and focused flux to attract and retain fasteners without magnetizing them, and an adjustable non-magnetic holder to secure the keeper and magnets, ensuring reliable attraction and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large, powerful magnets are used to magnetize the bit, then the bit can attract and retain fasteners, but high lateral force is generated perpendicular to the bit causing slipping and unreliable retention
Solution Approach 1:
The magnetic device is segmented into multiple pairs of magnets (e.g., four pairs) arranged around the bit, with each pair contributing to axial magnetic force. This segmentation distributes the magnetic force generation across multiple components rather than relying on a single large magnet, enabling controlled axial force with reduced lateral force components.
Solution Approach 2:
The magnetic flux is concentrated and directed locally through the keeper and into the fastener head, creating focused axial magnetic force at the critical interface between the bit and fastener. The alternating pole arrangement ensures that magnetic flux is directed primarily axially through the keeper rather than laterally, improving retention reliability.
2Force
If the bit is magnetized to attract fasteners, then fastener attraction is enabled, but the fastener becomes magnetized and is attracted to other magnetic items in its vicinity, reducing pickup reliability
Solution Approach 1:
The magnetic flux path is extracted and confined to a specific route through the keeper and fastener head, preventing magnetic flux from permeating into the fastener body. The keeper acts as a magnetic shield that channels flux axially, extracting the harmful magnetization effect from the fastener while preserving the necessary attraction force.
Solution Approach 2:
The keeper serves as an intermediary magnetic component between the magnets and the fastener. It conducts magnetic flux from the alternating pole magnets to the fastener head while preventing direct magnetization of the fastener body, thus mediating the magnetic interaction to achieve attraction without unwanted magnetization.
3Ease of manufacture
If magnetic devices are attached to fastener driving assemblies with set screws or magnetic force, then attachment is achieved, but the devices tend to slip and lose location in relation to the bit tip
Solution Approach 1:
The magnetic device incorporates an adjustable mechanism that allows dynamic positioning of the keeper and magnets relative to the bit. The adjustment feature enables the device to adapt to different bit lengths and wear conditions, maintaining optimal location stability throughout the tool's service life rather than being fixed at a single position.
4Reliability
If alternating pole magnets are arranged around the bit with a keeper, then axial magnetic force is provided to prevent slipping, but the device complexity increases
Solution Approach 1:
Multiple functional elements are merged into a compact integrated structure: the holder secures both the alternating pole magnets and the keeper in precise relative positions, while the adjustment mechanism integrates with the bit shaft. This merging reduces the number of separate components and simplifies assembly despite the sophisticated magnetic arrangement.
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 magnetic device efficiently utilizes axial magnetic force to attract and retain fasteners without magnetizing them, preventing attraction to other magnetic objects and ensuring reliable operation, while being adjustable for secure attachment to fastener driving assemblies.
Implementation Method 1
Each pair of magnets provides magnetic flux to the keeper and the fastener. Each pair of adjacent magnets provides a closed magnetic flux path through the first magnet of the pair, the keeper, the second magnet of the pair, and the fastener.
Implementation Method 2
The at least one pair of magnets provide magnetic flux to the keeper and the fastener. Each pair of adjacent magnets provides a closed magnetic flux path through the first magnet of the pair, the keeper, the second magnet of the pair, and the fastener.
Data Source
AI summary
A magnetic device for attracting and retaining a fastener which has a bit, a generally ring-shaped keeper having a bottom surface, at least some portion of which bottom surface is magnetized, at least one pair of magnets, each pair of magnets having two magnets with alternating poles, adjacent to the magnetic bottom surface of the keeper and arranged around the bit such that an even number of magnets with alternating poles is arranged around the bit, and a non-magnetic holder that secures the keeper and the magnets and surrounds the bit. The magnets provide magnetic flux to the keeper and the fastener. Each pair of adjacent magnets provides a closed magnetic flux path through a first magnet of the pair, the keeper, a second magnet of the pair, and the fastener. The location of the magnetic device along the bit may be adjustable or fixed.