Pressfitting Collar Triangular Teeth Eliminate Pipe Sleeve Folds
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Solution Overview
Problem
The increase in pipe diameters has led to material accumulation and the formation of longitudinal folds on the external metal sleeve during pressfitting, causing potential breakage, especially under temperature fluctuations, in existing pipe jointing technologies.
Innovation Solution
A pressfitting collar with mateable profiles consisting of continuous series of isosceles triangular teeth, where the vertices slightly copenetrate, eliminating rectilinear portions parallel to the pipe axis, and featuring chamfered edges for prevention of seizure, ensures a fold-free joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pressfitting collar with rectilinear end edges is used, then the pressfitting operation can be completed, but material accumulation forms longitudinal folds on the metal sleeve causing potential breakage
Solution Approach 1:
The end edges of the pressfitting collar are designed with curved profiles instead of rectilinear edges. Specifically, each end edge presents a profile with a triangular tooth configuration where the sides are inclined rather than straight, creating a curved contact path during pressfitting. This curvature prevents the concentration of stress and material accumulation that occurs with rectilinear edges, thereby eliminating the formation of longitudinal folds on the metal sleeve while maintaining complete pressfitting operation capability.
2Reliability
If the collar completely encloses the metal sleeve, then the joint is sealed, but material accumulation occurs at the contact region forming folds
Solution Approach 1:
The curved triangular tooth profiles on the collar's end edges create a progressive contact mechanism with the metal sleeve. As the collar closes, the curved surfaces guide the material flow smoothly around the sleeve circumference, preventing localized accumulation. The triangular configuration with inclined sides ensures continuous contact distribution rather than concentrated pressure points, thereby achieving complete enclosure and sealing without generating harmful folds.
Solution Approach 2:
The pressfitting collar applies different geometric characteristics to different regions of its end edges. The triangular tooth profiles with specific inclination angles create localized contact zones that distribute material flow appropriately. This local geometric optimization ensures that each region of the metal sleeve experiences appropriate pressure distribution, preventing material accumulation at critical locations while maintaining overall joint sealing.
Data Source
Figure 1~4
AI summary
The pressfitting collar (10), for pipe pressing tongs, comprises at least two jaws (12, 14, 16) hinged together, each comprising an arched pressfitting element (20, 21, 22) with a radius of curvature suitable for the pipe joint to be made. The facing end edges (24, 25) of the pressfitting elements (20, 22) of the two end jaws (12, 16) have respective shaped profiles which mate on completion of the pressfitting operation. The profiles of the two end edges (24, 25) are shaped completely as consecutive triangular teeth. The straight line (L1) joining the vertices of two consecutive triangular teeth of one (25) of the two edge profiles coincides with, or passes a certain distance beyond, the straight line (L2) joining the vertices of two corresponding consecutive triangular teeth of the other edge profile (24).