Coupling Nut Head Geometry for Uniform Torque Sealing
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Solution Overview
Problem
Existing coupling nuts in gas turbine engines experience deformation and inefficiencies in sealing due to the use of open-ended wrenches, which lead to non-uniform force distribution and potential leakage, as they can plastically deform and alter the sealing interface between the ferrule and nipple.
Innovation Solution
Designing coupling nuts with specific torque-transmitting face patterns, such as double-hexagonal, triple-square, and spline shapes, that prevent the use of open-ended wrenches and ensure engagement only with tools like double hexagonal flare crowfoot wrenches, distributing torque more uniformly and reducing deformation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open-ended wrenches are used to tighten coupling nuts, then ease of operation is improved, but manufacturing precision deteriorates due to non-uniform force distribution and plastic deformation
Solution Approach 1:
The coupling nut head features an asymmetric double-hexagonal cross-section with twelve substantially planar faces arranged in two hexagonal patterns. This asymmetric geometry prevents open-ended wrenches from applying force at multiple points simultaneously, forcing the use of specialized tools that apply torque at a single point to ensure uniform force distribution and prevent plastic deformation of the sealing interface.
2Ease of manufacture
If traditional hexagonal coupling nuts are used, then ease of manufacture is improved, but reliability deteriorates due to deformation and leakage risks
Solution Approach 1:
The coupling nut head is segmented into twelve distinct planar faces arranged in two hexagonal patterns, creating multiple discrete torque transmission surfaces. This segmentation allows specialized tools to engage with specific faces and apply torque uniformly, preventing the deformation and leakage associated with traditional hexagonal designs while maintaining manufacturability through standardized forming processes.
3Device complexity
If open-ended wrenches are used, then device complexity is reduced, but object-generated harmful factors increase due to ovalization and potential leakage
Solution Approach 1:
The double-hexagonal head geometry with twelve planar faces preliminarily prevents the harmful action of non-uniform torque application by open-ended wrenches. The specialized geometry inherently blocks the use of conventional tools that cause ovalization, forcing the use of tools designed to apply torque uniformly at a single point, thereby preventing deformation and leakage before they can occur.
Data Source
AI summary
A coupling nut for sealingly engaging a ferrule of a fluid line to a component of a hydraulic system, has: a shank extending along a central axis and having threads to engage a nipple, the threads extending circumferentially around the central axis, the shank defining an inner passage extending along the central axis and sized to receive the fluid line; and a head extending from the shank circumferentially around the inner passage relative to the central axis, the head: defining faces circumferentially distributed about the central axis and edges at junctions between the faces, the faces including torque-transmitting faces each facing a direction having a circumferential component relative to the central axis, and having a cross-section in a plane normal to the central axis, the cross-section defining a plurality of symmetry planes containing the central axis, the torque-transmitting faces free of intersection with the plurality of symmetry planes.