Restrained Pipe Gasket With Toothed Segments for Plastic Joint Locking
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Solution Overview
Problem
Existing pipe gaskets fail to effectively restrain plastic pipes under high pressure applications, as they either destructively impinge upon the pipes or require costly and complex manufacturing processes, and existing solutions for plastic pipes lack sufficient axial restraint against thrust forces.
Innovation Solution
A pipe gasket with toothed, metal locking segments that are embedded within a compressible annular body, allowing for hand assembly and retrofitting of existing Rieber gasket-containing plastic bells, with the segments' design and arrangement optimizing stress distribution to prevent pipe separation without destructive impingement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toothed metal segments are used to prevent pipe separation, then axial restraint against thrust forces is improved, but destructive radial loads are generated on the pipe surfaces
Solution Approach 1:
The locking segments are designed with differentiated surface characteristics: a smooth radially outer surface that contacts the bell without impingement, and a radially inner surface with axial protrusions (teeth) that engage the spigot. This local quality differentiation allows the segment to provide axial restraint through the inner teeth while the smooth outer surface prevents destructive radial loads on the bell.
Solution Approach 2:
The gasket is divided into multiple discrete locking segments distributed around its inner perimeter, each independently providing axial restraint. This segmentation allows the restraining function to be distributed, reducing the concentration of radial loads at any single location while maintaining overall axial restraint capability.
2Ease of operation
If conventional gaskets are used for plastic pipes, then ease of assembly is maintained, but sufficient axial restraint against thrust forces is not achieved
Solution Approach 1:
The locking segments are spring-loaded or resiliently mounted within the gasket body, enabling them to automatically engage with the spigot teeth upon insertion without requiring external tools or complex assembly procedures. The segments self-adjust to provide axial restraint as the pipe is inserted, maintaining ease of assembly while achieving reliable thrust force resistance.
3Reliability
If metal segments with acute teeth are used for restraint, then axial locking capability is improved, but insertion force requirements increase due to friction
Solution Approach 1:
The locking segments feature a smooth radially outer surface that minimizes friction during insertion as it contacts the bell, while the radially inner surface contains the axial protrusions for locking. This local quality differentiation reduces the overall insertion force requirement by eliminating friction from the outer surface while preserving axial locking capability through the inner teeth.
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 gasket effectively prevents separation of plastic pipes under thrust forces while reducing insertion force requirements and eliminating the need for external harnesses, enhancing the structural integrity and ease of assembly of plastic pipe joints.
Implementation Method 1
a compressible annular body and a plurality of rigid segments partially embedded within the compressible annular body
Implementation Method 2
The toothed metal segments bite into the outer surface of the spigot of the inserted pipe and prevent withdrawal of the inserted pipe from a bell end of the other pipe
Data Source
AI summary
A gasket for preventing the separation of a pipe joint formed between plastic pipes such as pipes manufactured from PVC. The invention provides an internally restrained pipe joint including a bell with a substantially V-shaped annular groove. The annular groove includes a front radial wall and a rear radial wall and a gasket seated in the annular groove. The gasket includes an inner radial face, an opening defined by the inner radial face and an outer radial face with a front radial section located adjacent to the front radial wall of the annular groove and a rear radial section located adjacent to the rear radial wall of the annular groove. A plurality of toothed, rigid restraining segments is at least partially embedded in the gasket.