Push-fit Fitting End Bushing Retention Mechanism
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Solution Overview
Problem
Push-fit fittings with metal bodies, such as supply stop valves, face issues with work hardening and dezincification when operated under fluid pressure, leading to potential cracking and weakening of the housing, especially when in contact with the ground.
Innovation Solution
The design employs a metal housing with a non-rolled end bushing and gripper rings that use a flexible plastic end bushing with a rib and groove arrangement to secure the O-ring and gripper rings, eliminating the need for a threaded connection and allowing for secure operation under high fluid pressures without risking dislodgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the body end portion is rolled to retain the end bushing and components, then the components are secured within the body, but the body undergoes work hardening and cracking under fluid pressure
Solution Approach 1:
The invention removes the rolled end portion from the body structure. Instead of rolling the metal body to retain components, the patent uses a separate retention mechanism (such as a snap-fit ring or separate retaining structure) that does not require deforming the main body, thereby eliminating work hardening and cracking while still securing the end bushing and components effectively
2Reliability
If the body end portion is rolled to retain components, then the components are secured within the body, but dezincification occurs and weakens the housing
Solution Approach 1:
The invention extracts the rolling operation from the body end portion, eliminating the localized deformation that creates susceptibility to dezincification. The retained components are secured through an alternative mechanism that does not involve rolling the brass housing, thereby preventing the chemical degradation and strength loss associated with dezincification
3Reliability
If a threaded connection is used to secure the end bushing, then the connection is secure, but the device complexity increases
Solution Approach 1:
The invention replaces the threaded mechanical connection system with a simpler retention mechanism, such as a snap-fit arrangement, interference fit, or deformable ring that secures the end bushing without requiring threads. This substitution maintains the security of the connection while significantly reducing the complexity of the overall structure
Data Source
AI summary
A plumbing fitting couplable with a free-end portion of a pipe. The fitting has a chamber with an opening and an interior chamber wall with a circumferentially extending chamber groove, and an end bushing with an interior opening sized to receive the pipe free-end portion and an exterior wall portion having an outwardly projecting, circumferentially extending locking member within the chamber groove to resist movement of the end bushing out of the first chamber opening. A seal and gripper ring within the chamber seal with and releasably grip the pipe free-end portion. The end bushing interior opening has an end bushing interior wall portion sized to be engaged by the free-end portion of the pipe when within the end bushing interior opening to resist disengagement of the locking member from the chamber groove while the free-end portion of the pipe is within the end bushing interior opening.