Load Reaction Jig for High-Torque Fastener Installation
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Solution Overview
Problem
The installation of high-torque nut and bolt fasteners using hand-held power tools poses a risk of tool counter-rotation, potentially injuring the operator or damaging the tool and structure, and existing solutions like reaction arms are cumbersome and unsuitable for restricted access applications.
Innovation Solution
A method involving a load reaction jig that secures a power tool to a fastener, allowing the counter-rotation force to be reacted into the jig and then into another fastener, eliminating the need for a bulky reaction arm and enabling secure tightening of multiple fasteners without moving the jig.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reaction arm is used to prevent tool counter-rotation during high-torque fastener installation, then tool stability is improved, but device complexity and weight increase
Solution Approach 1:
The reaction arm is divided into separate components: a stationary reaction structure attached to the workpiece, and a movable coupling device that connects the power tool to the reaction structure. This segmentation eliminates the need for a single bulky reaction arm while achieving the same counter-rotation prevention function.
Solution Approach 2:
The reaction structure serves as an intermediary element between the power tool and the workpiece. Instead of directly reacting forces through a large reaction arm, the intermediary reaction structure with positioning stops provides a stable reference point that prevents tool counter-rotation while reducing overall system complexity.
2Reliability
If a reaction arm is used to prevent tool counter-rotation, then tool stability is improved, but the size of the tooling increases
Solution Approach 1:
Instead of attaching a large reaction arm to the power tool to prevent counter-rotation, the solution inverts the approach by attaching a compact reaction structure to the workpiece and coupling the tool to this stationary structure. This inversion reduces the moving volume while maintaining stability.
Solution Approach 2:
The reaction structure utilizes the workpiece itself as the reaction surface, distributing the counter-rotation prevention function across the workpiece structure rather than concentrating it in a large reaction arm. This dimensional distribution reduces the volume of moving components.
3Reliability
If a reaction arm is used to prevent tool counter-rotation, then tool stability is improved, but ease of operation deteriorates
Solution Approach 1:
The reaction structure is pre-positioned on the workpiece with positioning stops that align with specific features of the workpiece. This preliminary positioning eliminates the need for complex alignment procedures when installing the power tool, improving ease of operation while maintaining stability.
4Reliability
If a reaction arm is used to prevent tool counter-rotation, then tool stability is improved, but adaptability to restricted access applications deteriorates
Solution Approach 1:
By segmenting the reaction system into a stationary reaction structure and a movable coupling device, the system can be configured for restricted access applications. The coupling device can be positioned in tight spaces while the reaction structure remains on the accessible workpiece surface, enabling operation in previously inaccessible areas.
Data Source
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Figure 3
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AI summary
A method of installing a plurality of nut and bolt fasteners (300) upon a structure (100, 200) is described. The method comprises placing a jig (400) around the nut (301) of a first fastener (300) and the nut (301) of a second fastener (300), securing the jig (400) to the first fastener (300), and then using a power tool (600) to tighten the nut of the second fastener (300) to a target torque. The step of tightening the nut comprises engaging a socket portion (709) of the power tool (600) with the nut, securing the power tool (600) to the jig (400) such that a handle portion of the power tool (600) is prevented from rotating about an axis of rotation of a socket portion (709) of the power tool (600) when the nut is being rotated by the socket portion (700). This application also describes a jig (400), jig fasteners (500) for securing a jig (400) to a fastener (300), and a fastening head (700) for a power tool (600).