Pipe Joint Separation Prevention Device Axial Claw Overlap
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Solution Overview
Problem
Conventional separation prevention devices for pipe joints often cause stress concentration and cracking in the lining layer due to pipe deformation, especially when subjected to external forces like earthquakes or differential settlement, as the claws' shearing stress acts on the non-contact regions between the claws and the pipe.
Innovation Solution
The solution involves arranging the claws of adjacent disengagement prevention members to overlap in the axial direction, creating a continuous contact region that reduces stress concentration and enhances the separation preventing effect by increasing the contact ratio with the outer peripheral surface of the inserting opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the claws of disengagement prevention members are arranged at multiple locations in the circumferential direction, then the separation preventing effect is improved, but stress concentration occurs in the non-contact regions between claws causing cracks in the lining layer
Solution Approach 1:
The patent transitions from a single circumferential arrangement of claws to a two-dimensional overlapping arrangement where claws are positioned in both the circumferential direction and the axial direction. This dimensional change allows claws to overlap when viewed from the axial direction, ensuring continuous contact along the inserting opening's outer peripheral surface and eliminating non-contact regions that cause stress concentration.
Solution Approach 2:
The patent achieves continuous contact between the claws and the outer peripheral surface of the inserting opening by arranging claws to overlap in the axial direction. This continuity eliminates gaps or non-contact regions between adjacent claws, ensuring that the entire surface is covered and stress is distributed evenly without concentration points that would lead to cracking.
2Reliability
If the contact region of claws with the outer peripheral surface is limited to 80-90%, then the device structure remains simple, but the separation preventing effect is insufficient against strong external forces
Solution Approach 1:
The patent adds the axial direction as a second dimension for claw arrangement, creating an overlapping pattern that increases the contact ratio to 100% or more. This dimensional approach allows multiple claws to engage the same region from different axial positions, maximizing contact without requiring additional circumferential locations or complex mechanisms.
Solution Approach 2:
The patent merges the functional roles of multiple claws by arranging them to overlap in the axial direction. Instead of distributing claws only circumferentially, the overlapping arrangement allows adjacent claws to share the load and contact the same region of the inserting opening, effectively combining their separation prevention functions and achieving complete surface coverage.
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 arrangement effectively prevents damage to the lining layer and improves the separation preventing effect against strong external forces by ensuring continuous contact and distributing stress evenly, thereby enhancing the device's ability to withstand earthquakes and differential settlement.
Implementation Method 1
A claw is formed on the inner peripheral surface of the disengagement prevention member. The disengagement prevention member is pressed by the pressing member, the claw is made to bite into an outer peripheral surface of the inserting opening and engage with the outer peripheral surface
Implementation Method 2
the claw is made to bite into an outer peripheral surface of the inserting opening and engage with the outer peripheral surface, thereby exhibiting a separation preventing effect
Data Source
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AI summary
A separation prevention device for a pipe joint has disengagement prevention members and a pressing member. The disengagement prevention members are disposed at a plurality of locations in a circumferential direction of the pipe, on an inner peripheral surface of an engaging tool or of a receiving opening itself and which are formed with claws. The pressing member presses the disengagement prevention member radially inward to the pipe and which engages the claw with the outer peripheral surface of an inserting opening. The claw of the disengagement prevention member and the claw of the disengagement prevention member which is adjacent to the former disengagement prevention member in the circumferential direction of the pipe are arranged so as to overlap each other in the axial direction of the pipe in a state where the claws are engaged with the outer peripheral surface of the inserting opening.