Lock-Ring Pipe Joint Structure for Higher Bending Rigidity
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Solution Overview
Problem
Conventional pipe joints with separation preventive functions fail to achieve sufficient bending rigidity, especially when the diameter of the pipes is large, due to the limitations of using a cylindrical liner to counteract thrust forces.
Innovation Solution
A pipe joint design that includes a spigot and socket with a lock ring-accommodating groove and an engaging part, along with a bending suppressing member and an expansion/contraction suppressing member, which restricts the socket and spigot in the bending and axial directions, respectively, to enhance bending rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a cylindrical liner is mounted between the spigot and socket to prevent separation, then the pipe joint can counteract thrust force, but the bending rigidity of the pipe joint is insufficient especially when the diameter of the pipes is large
Solution Approach 1:
The invention divides the thrust resistance function into two separate components: a liner that prevents separation and a bending suppressing member that provides bending rigidity. This segmentation allows each component to be optimized for its specific function, with the bending suppressing member being a ring-shaped structure with radial thickness specifically designed to resist bending moments while the liner handles the separation prevention
Solution Approach 2:
The invention adds a new dimensional element by introducing a ring-shaped bending suppressing member with significant radial thickness between the liner and the spigot outer circumference. This radial dimension provides the necessary moment of inertia to resist bending forces, which the cylindrical liner alone cannot provide. The bending suppressing member extends radially outward from the liner to the spigot surface, creating a thick-walled cylindrical structure that resists bending
2Adaptability or versatility
If the pipe joint allows expansion and contraction to accommodate pipe line movement, then the pipe joint remains flexible, but the bending rigidity is insufficient to counteract thrust force
Solution Approach 1:
The invention segments the mechanical functions by placing the bending suppressing member between the liner and the spigot, creating distinct zones: the inner liner zone for separation prevention, the intermediate bending suppression zone with thick radial structure, and the outer spigot zone. This segmentation allows the liner to accommodate axial movement while the intermediate ring structure resists bending
Solution Approach 2:
The bending suppressing member provides localized stiffness exactly where needed - in the radial direction between the liner and spigot - while allowing axial flexibility through the liner. The ring-shaped structure with radial thickness creates local rigidity in the bending direction without constraining axial expansion and contraction movements
Data Source
AI summary
In a pipe joint, a spigot is inserted into a socket; a lock ring is accommodated in a lock ring-accommodating groove formed in the inner circumference of the socket; and an engaging part formed in the outer circumference of the spigot, wherein the engaging part engages with the lock ring from a back side of the socket in a separation direction A of the spigot, thereby preventing the spigot from separating from the socket. The engaging part is formed at a position receding from a distal end of the spigot in the separation direction A of the spigot. A bending suppressing member for restricting the socket and the spigot in a bending direction C is provided between the inner circumference of the socket and the outer circumference of the spigot in the range between the distal end of the spigot and the engaging part.