Conduit Fitting Ferrule Assembly for Repeatable Torque Pull-Up
Find Innovative SolutionsGenerate Solutions
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, necessitating experienced assemblers and leading to issues like galling and torque-related problems.
Innovation Solution
A stroke resisting member, such as a torque collar, is integrated or attached to the fitting components to provide a controlled axial displacement and torque increase, allowing for pull-up by torque or turns, and facilitating multiple remakes with consistent performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferrule type fittings are pulled-up by turns without a stroke resisting member, then the fitting can be assembled, but there is no reliable and repeatable association between pull-up torque and number of turns, leading to galling and torque-related problems
Solution Approach 1:
A stroke resisting member is introduced as an intermediary element between the threaded fitting components. This member provides a controlled axial displacement that creates a reliable torque-stroke association, enabling repeatable pull-up operations without requiring experienced assemblers to count turns precisely. The stroke resisting member mediates the relationship between torque application and ferrule deformation, preventing galling and torque-related problems.
2Manufacturing precision
If the number of turns is controlled to achieve complete grip and seal, then the ferrules effectively grip and seal the conduit, but precise turn counting is required and torque-related problems occur
Solution Approach 1:
The stroke resisting member provides self-service by automatically controlling the axial displacement and torque characteristics during assembly. As the threaded components are tightened, the stroke resisting member engages and provides a controlled resistance that self-regulates the pull-up process, ensuring complete grip and seal without requiring the assembler to precisely count turns or have specialized training.
3Ease of repair
If fittings are loosened and re-tightened for repair and maintenance, then maintenance activities can be performed, but the same fitting components and ferrules are reused which may compromise performance
Solution Approach 1:
The stroke resisting member provides beforehand cushioning for remake operations. During initial assembly, the stroke resisting member controls the axial displacement and prepares the fitting for future remakes. When the fitting is loosened and re-tightened, the stroke resisting member ensures consistent torque-stroke characteristics, maintaining reliability across multiple maintenance cycles without requiring replacement of ferrules or other components.
Data Source
AI summary
A subassembly for a conduit fitting includes a first ferrule and a second ferrule alignable relative to an axis. The first ferrule includes a camming surface at a back portion thereof, and the second ferrule includes a surface that contacts the camming surface when the first ferrule and the second ferrule are axially moved together along the axis. A retaining structure retains the first ferrule and the second ferrule together as a subassembly, and includes a flange extending radially outward and axially rearward from the back portion of the first ferrule to define an outer diameter recess. The flange includes an end portion that extends radially inward to define an inner diameter recess retaining a forward portion of the second ferrule. The outer diameter recess and the inner diameter recess together define a hinge portion of the flange.