Conduit Fitting Stroke Limiter for Repeatable Pull-Up Assembly
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Solution Overview
Problem
Conventional conduit fittings lack a reliable and repeatable association between pull-up torque and the number of turns required to achieve a complete grip and seal, making it difficult to consistently remake fittings without experienced assemblers and leading to issues like galling and torque-related problems.
Innovation Solution
The introduction of a stroke resisting member, which can be integral or non-integral with the threaded fitting component, that deforms axially to provide a controlled relative axial displacement, allowing for pull-up by torque or turns, and includes a gauging feature to ensure proper pull-up conditions are maintained across multiple remakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferrule type fittings are pulled-up by turns with controlled relative stroke, then the ferrules can effectively grip and seal the conduit, but it requires experienced assemblers and precise control of turns and partial turns
Solution Approach 1:
The fitting incorporates a stroke resisting member that automatically limits the relative axial displacement between fitting components during tightening. This self-limiting mechanism eliminates the need for operators to manually count turns or control stroke, as the fitting itself controls the displacement to achieve proper ferrule engagement and seal.
Solution Approach 2:
The patent replaces the manual mechanical control system (turn counting, stroke measurement) with a passive mechanical limit imposed by the stroke resisting member. The geometric constraint of the stroke resisting member substitutes for the operator's skill and attention in controlling the tightening process.
2Reliability
If fittings are tightened with precise torque control to achieve complete grip and seal, then reliable connection is achieved, but torque-related problems and galling occur
Solution Approach 1:
The invention changes the controlling parameter from torque (which causes galling and harmful effects) to axial displacement (controlled by the stroke resisting member's geometry). By limiting the relative axial displacement between components, the fitting achieves reliable connection without excessive torque that would cause galling or other torque-related damage.
3Ease of repair
If fittings are remade multiple times with replacement of parts, then the fluid system can be maintained, but consistent performance across remakes is difficult to achieve
Solution Approach 1:
The stroke resisting member is pre-configured with specific geometric dimensions that encode the correct relative axial displacement required for proper ferrule engagement. This preliminary configuration ensures that every time the fitting is assembled or remade, the components automatically achieve the correct positioning, maintaining consistent performance across multiple remakes regardless of which specific parts are used.
4Adaptability or versatility
If the stroke resisting member is made non-integral with the threaded fitting component, then assembly flexibility is improved, but device complexity increases
Solution Approach 1:
The fitting is divided into separate components: the threaded fitting component and the stroke resisting member. This segmentation allows the stroke resisting member to be independently configured with optimal geometric dimensions and removed or replaced without affecting the threaded component. The separate parts provide assembly flexibility while the simple geometric constraint keeps the overall device complexity manageable.
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
This solution enables reliable and repeatable pull-up and remake operations, reducing the need for precise torque control and turn counting, while maintaining the integrity of the conduit grip and seal, allowing for multiple reliable remakes with consistent performance.
Implementation Method 1
a stroke resisting member that deforms axially to provide a controlled relative axial displacement
Implementation Method 2
the stroke resisting member deforms axially to provide a controlled relative axial displacement, allowing for pull-up by torque or turns
Data Source
AI summary
A fitting includes a first and second threaded fitting component and a conduit gripping device receivable within the first threaded fitting component. A stroke resisting member is integral with the first threaded fitting component and includes a web having a first radial thickness and extending axially inward from the first threaded fitting component to a distal ring portion having a second radial thickness greater than the first radial thickness. A radially extending bearing surface of the distal ring portion axially engages a radially extending portion of the second fitting component when the first and second fitting components are joined together to the first relative axial position. The stroke resisting member resists additional axial stroke of the first and second fitting components, such that a tightening torque beyond the first relative axial position is increased by the axial engagement.