Pipe Joint Stop Ring Teeth for Flareless Sealing and Pull-Out Resistance
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Solution Overview
Problem
Existing pipe joints, such as the one described in JP 5091191 B2, face issues including relative slip between tapered parts during cap nut threading, poor working efficiency due to the need for preliminary working, and reduced hermeticity and extraction resistance due to pipe thickness reduction during tightening.
Innovation Solution
A pipe joint configuration that includes a flare joint body with a male screw part and a slope surface, a cap nut with a female screw part and a housing space part featuring a tapered section with a reduced-diameter tip, and a stop ring with a plastically-deformable cylindrical thin part and pipe extraction preventing tooth parts. The tooth parts, including back and front teeth, are arranged at a tiny interval and designed to tightly contact the pipe outer peripheral surface, generating significant pipe extraction resistance and ensuring hermetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flared part is provided at the end portion of the pipe using plastic forming, then hermeticity is ensured through pressure contact between metallic surfaces, but preliminary working is required which reduces working efficiency and may cause cracks at the flared part edge
Solution Approach 1:
The invention extracts and eliminates the flared part from the pipe structure. Instead of forming a flared part at the pipe end, the patent uses a straight pipe end that inserts into the joint body, completely removing the need for preliminary flaring operations and associated cracks while maintaining hermeticity through the O-ring sealing mechanism
Solution Approach 2:
The invention introduces an O-ring as an intermediary sealing element between the pipe end and the joint body. This O-ring mediator provides hermetic sealing without requiring metallic pressure contact or flared parts, thereby eliminating the need for preliminary working operations
2Reliability
If the cap nut is tightened to ensure hermeticity, then the pipe thickness is reduced which increases the likelihood of hermeticity loss or cap nut loosening
Solution Approach 1:
The invention uses a disposable O-ring sealing element that provides hermetic sealing without requiring high tightening forces that would thin and weaken the pipe. The O-ring is sacrificed or compressed to provide sealing, eliminating the need to compromise pipe structural integrity through excessive tightening
Solution Approach 2:
The O-ring acts as an intermediary that provides hermetic sealing at lower pressures, preventing direct high-pressure contact between the cap nut and pipe that would cause pipe thinning and strength reduction
3Strength
If the pawl is designed to bite into the pipe outer peripheral surface, then extraction resistance is improved, but preliminary working is required which seriously reduces working efficiency
Solution Approach 1:
The invention eliminates the need for preliminary working by designing the pawl structure to automatically engage with the pipe outer peripheral surface during the normal tightening process. The pawl's inclined surface allows it to ride over and then bite into the pipe surface as the cap nut is threaded on, providing extraction resistance without separate preliminary operations
Solution Approach 2:
The pawl structure is designed to self-engage with the pipe surface during tightening. The inclined surface of the pawl allows it to automatically find and bite into the pipe outer peripheral surface without requiring external preliminary working tools or operations
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 proposed pipe joint design eliminates the need for preliminary working, enhances working efficiency, and provides excellent hermetic performance and extraction resistance, even under bending forces, thereby preventing pipe extraction accidents.
Implementation Method 1
a stop ring (3) fitted in the housing space part (E), including a base-end pressure-contacting slope surface (32) contacting the slope surface (5) with reduced-diameter tip under pressure, and having a tip provided with a plastically-deformable and substantially cylindrical thin part (35)
Implementation Method 2
the first tip side (41) of the back tooth (36B) and the second tip side (42) of the front tooth (36F) come into a state of tightly contacting the outer peripheral surface (10A) of the straight tip part (10) of the connection target pipe (P) under pressure to generate the pipe extraction resistance (Z)
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
[Problem] To provide a pipe joint allowing reliable connection to a pipe P without flaring. [Means of solving problem] The pipe joint includes a flare joint body 1F, a cap nut 2, and a stop ring 3. A curved pressure-contacting slope surface 32 of the stop ring 3 contacts a slope surface 5 with reduced-diameter tip of the flare joint body 1F under pressure to establish sealing by means of mutual contact between metallic surfaces. The pipe P is grasped in a tightly pressure-contacting state using a back tooth and a front tooth formed at a tip head 37 of a substantially cylindrical thin part 35 of the stop ring 3.