Shrouded Pipe Coupling With Visual Stop for Over-Tightening
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Solution Overview
Problem
Existing mechanical pipe couplings face challenges in ensuring proper assembly and avoiding excessive tightening, especially when pipe elements are out of specification or intended for partial contact, leading to potential high stresses in bolt and nut assemblies, particularly with the use of battery-powered impact wrenches that lack torque feedback.
Innovation Solution
The design incorporates shrouds and recesses on attachment members that pivot and engage to provide a visual indication of proper assembly, using index marks and a hinge mechanism to ensure correct alignment and contact, preventing over-tightening by blocking the line of sight to the gasket and providing a clear visual confirmation of satisfactory joint contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the installer continues to tighten the bolts to attempt to achieve planar face-to-face contact, then the visual gap between the bolting faces closes, but high stresses are created within the bolt and nut assemblies
Solution Approach 1:
The patent applies feedback by providing visual indicators (index marks) that give real-time information to the installer about the assembly state. When the index marks align, it feedbacks that proper contact has been achieved, preventing continued tightening that would create excessive stress. This resolves the contradiction by enabling precise stopping point detection.
Solution Approach 2:
The patent replaces the mechanical feedback system (physical contact between faces) with a visual indication system (index marks). Instead of relying on the installer to feel or see the gap close between bolting faces, the index marks provide a clear visual signal when proper contact is achieved, substituting tactile/mechanical sensing with optical indication to prevent over-tightening.
2Power
If battery powered impact wrenches are used to tighten the nut and bolt assemblies, then very high torque can be applied, but very little physical feedback is provided to the installer of the torque being achieved
Solution Approach 1:
The patent introduces visual feedback through index marks that allow the installer to monitor assembly progress even when using high-power impact wrenches that provide minimal tactile feedback. The alignment of index marks serves as an objective stopping criterion, enabling safe use of high-torque tools without risking over-tightening due to lack of feedback.
Solution Approach 2:
The index marks act as an intermediary between the high-power impact wrench and the installer. Instead of the installer directly sensing torque through physical feedback, the index marks mediate by providing visual information about the assembly state, allowing safe operation of powerful tools without direct tactile connection to the fastening process.
3Adaptability or versatility
If the coupling is assembled with pipe that is grooved incorrectly, out of round, or out of specification, then the pipe elements may not achieve proper alignment, but the installer needs a clear visual indication of proper assembly
Solution Approach 1:
The patent provides unambiguous visual feedback through index marks that indicate when the coupling segments are properly assembled. Even when pipe variations prevent perfect planar contact, the index marks provide a clear stopping point, enabling the installer to achieve acceptable assembly without needing perfect pipe alignment. This resolves the contradiction by decoupling the visual indication from perfect face-to-face contact.
Data Source
AI summary
Couplings for joining pipe elements have segments with attachment members with faces which contact one another when the segments are properly installed on the pipe elements. Each segment has one or more shrouds and recesses positioned along the faces. The shrouds on one segment are received within respective recesses on the other segment. The shrouds block the line of sight toward the central space which the segments surround and which receives the pipe elements. Index markings on the segments show visual inspection points to confirm proper engagement between the segments and the pipe elements.