Torque-Limiting Fitting Prevents Ferrule Over-Compression
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Solution Overview
Problem
Existing fluid-handling device fittings often lead to fluid leakage or ferrule degradation due to over-tightening or under-tightening, as they fail to maintain sufficient compression of the compressible ferrule without compromising its integrity or disrupting fluid flow.
Innovation Solution
A torque fitting with a threaded body portion and a torque-limiting body portion, arranged concentrically, that applies torque in a compressive direction until a threshold is reached, preventing further rotation and thus preventing over-compression of the ferrule, while allowing decompressive rotation to ensure sufficient compression and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque is increased to ensure sufficient compression of the ferrule, then fluid leakage is prevented, but ferrule degradation and over-compression occur
Solution Approach 1:
The patent changes the mechanical parameter of torque by introducing a torque-limiting body portion with a predetermined torque threshold. This threshold mechanism automatically adjusts the compression force applied to the ferrule, ensuring sufficient compression to prevent leakage while preventing excessive torque that would cause ferrule degradation. The torque threshold acts as a controlled parameter change point.
Solution Approach 2:
The patent implements a feedback mechanism through the torque-limiting body portion that senses when the predetermined torque threshold is reached. When the threshold is exceeded, the mechanism provides feedback by preventing further rotation of the threaded body portion, thereby automatically adjusting the compression force to maintain ferrule integrity while ensuring adequate sealing.
2Reliability
If torque is increased to prevent fluid leakage, then sealing is improved, but ferrule deformation and flow disruption occur
Solution Approach 1:
The patent introduces a predetermined torque threshold parameter that automatically controls the compression force. This parameter change mechanism ensures the ferrule is compressed sufficiently for sealing while preventing the excessive compression that would cause deformation and disrupt fluid flow through the ferrule.
Solution Approach 2:
The torque-limiting body portion is designed beforehand with a predetermined torque threshold that acts as a cushioning mechanism. This pre-set threshold prevents excessive torque application before it can cause ferrule deformation, thereby protecting the ferrule from harmful over-compression while ensuring adequate sealing.
3Ease of operation
If the fitting allows free rotation for easy installation, then ease of operation is improved, but over-tightening cannot be prevented
Solution Approach 1:
The patent implements a dynamic torque control mechanism where the fitting transitions from a free-rotation state during installation to a locked state when the predetermined torque threshold is reached. The torque-limiting body portion allows easy rotation during installation but automatically prevents further rotation when excessive torque is applied, providing both ease of operation and torque control.
Solution Approach 2:
The fitting provides feedback during installation by allowing free rotation initially for ease of operation, then automatically sensing when the predetermined torque threshold is reached. The feedback mechanism prevents further rotation, thereby preventing over-tightening while maintaining ease of installation up to the safe torque limit.
4Ease of manufacture
If the fitting structure is simplified for ease of manufacture, then manufacturing cost is reduced, but torque-limiting functionality is lost
Solution Approach 1:
The patent merges the torque-limiting functionality into the existing fitting structure by integrating the torque-limiting body portion with the threaded body portion. This consolidation allows the fitting to maintain its basic simple structure for ease of manufacture while incorporating the torque-control feature that prevents over-tightening and ensures reliable operation.
Solution Approach 2:
The fitting is designed with multi-functionality by combining the sealing function, torque control function, and installation function into a single integrated structure. The torque-limiting body portion serves multiple purposes: it provides torque control, prevents over-tightening, and maintains the fitting's basic structural simplicity, thereby achieving reliability without sacrificing ease of manufacture.
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 fluid leakage and ferrule degradation by ensuring appropriate compression without over-tightening, allowing for efficient fluid flow while maintaining the integrity of the ferrule, indicated by a significant drop in rotational resistance and an audible click when the appropriate compression is reached.
Implementation Method 1
The lever preferably is configured with a degree of elasticity sufficient to enable repetitive flexion of the lever
Data Source
AI summary
An assembly comprises a multi-use torque fitting, a length of tubing, and a compressible ferrule, wherein the assembly is configured to couple an end of the length of tubing to a port of a fluid-handling device in a hermetically sealed or substantially leak-proof manner. Generally, the fitting is configured to provide a degree of compression to the compressible ferrule sufficient to prevent fluid leakage at the ferrule/port interface. This fitting generally comprises a threaded body portion and a torque-limiting body portion, wherein the threaded body portion and the torque-limiting body portion are arranged concentrically along a longitudinal axis of the fitting.