Split Tool Collet Shear Locking for Smooth Shaft Lanyards
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Solution Overview
Problem
Existing hand tool tethering devices fail to securely attach lanyards to metal shafts like punch pins and drift pins, leading to potential tool drops due to the lack of a 'shoulder' to prevent the tether from sliding off, especially under the high forces exerted when these tools are suddenly stopped by a safety lanyard.
Innovation Solution
A tool collet with a collet body, lanyard ring, and fastening members, featuring an annular groove and setscrews that create a shear across the fastener, securely attaching the collet to the hand tool and allowing the lanyard ring to slide within the groove, providing a stable attachment point even on tapered tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tether is attached to a tool handle using existing methods (molded sleeves, rubber caps, friction engagement), then the attachment is simple and easy to install, but the attachment fails under high forces when the tool is suddenly stopped, causing the tether to slide off
Solution Approach 1:
The collet body is divided into two separate components (first body component and second body component) that can be assembled around the tool shaft. This segmentation allows the tether attachment to be installed without removing the tool from service and enables the components to be independently optimized for different functions (clamping vs. tether retention).
Solution Approach 2:
The invention adds a radial dimension to the tether attachment by creating an annular groove that circumferentially encircles the tool shaft. This radial configuration prevents the tether from sliding off in any direction, not just axially, thereby improving reliability without requiring a more complex overall structure.
2Strength
If the collet body components are held together without additional fastening, then the structure is simpler, but the components cannot withstand the shear forces generated when the tool is arrested by the safety lanyard
Solution Approach 1:
A shear fastener is introduced as an intermediary element between the first and second body components. This fastener directly resists the shear forces generated during tool arrest, transferring loads between the components without requiring complex interlocking mechanisms or additional fastening elements.
Solution Approach 2:
The fastening mechanism is localized to specific regions where shear forces are most critical. The shear fastener is positioned to directly counteract the directional shear forces generated when the tool is arrested, providing strength precisely where needed rather than uniformly throughout the entire structure.
3Manufacturing precision
If the annular groove is positioned exactly at the interface between body components, then the lanyard ring positioning is more precise, but the fastener hole alignment becomes more difficult to manufacture
Solution Approach 1:
The annular groove is deliberately positioned asymmetrically relative to the body component interface, specifically offset toward the second body component. This asymmetric positioning decouples the groove location from the fastener hole alignment requirements, allowing each feature to be manufactured independently with standard tolerances while maintaining reliable lanyard ring retention.
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 solution effectively prevents tool drops by creating a secure lanyard attachment point that withstands the forces exerted when the tool is arrested by the safety lanyard, ensuring the lanyard remains attached and the tool is safely secured.
Implementation Method 1
tightening the setscrew against the hand tool sufficient to cause the first body component and the second body component to slide in opposite directions transversely relative to the hand tool, thereby creating a shear between the one or more fastening members and a fastener opening of the tool collet
Implementation Method 2
The hollow member is made of rubber or plastic and the wall of the hollow member frictionally engages or grips a tool located in the hollow member
Data Source
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AI summary
An apparatus and method of creating a shear across a fastener for a tool collet being attached to a hand tool includes providing a tool collet having a collet body with a peripheral body surface and a collet through opening where the collet body is divided into a first body component and a second body component and where one of the first body component and the second body component has a first radial through aperture extending from the peripheral body surface to the collet through opening, providing a setscrew within the first radial through aperture, inserting a hand tool into the collet through opening, securing the first body component to the second body component, and tightening the setscrew against the hand tool sufficient to cause the first body component and the second body component to slide in opposite directions transversely to the portion of the hand tool.