Peened Pipe Grip Element for Coated and Soft Pipe Couplings
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Solution Overview
Problem
Existing coupling devices for pipes, particularly those with grip elements featuring dents pressed out of plane adjacent to slit-like openings, face issues with reduced tensile strain resistance on pipes with protective coatings and softer pipes, where the grip element can act as a 'cheese slicer' leading to loss of grip over time.
Innovation Solution
The grip element's dents are modified by a peening operation before being pressed out of plane, enhancing their hardness, and a pressure member with protrusions is used to counteract the 'cheese slicer' effect and improve force transfer, allowing the use of cheaper base materials without compromising durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dents are pressed out of plane adjacent to slit-like openings in the grip element, then tensile strain resistance is improved on hard pipes, but the grip element acts as a cheese slicer on softer pipes causing loss of grip
Solution Approach 1:
The patent applies different surface treatments to different regions of the grip element. Specifically, the outer peripheral surface is given a different roughness or treatment compared to the inner peripheral surface, allowing optimized interaction with both hard and soft pipes without compromising either tensile resistance or grip stability
Solution Approach 2:
The patent modifies the physical parameters of the grip element surface by controlling the roughness values (Ra, Rz) of different surfaces. The inner peripheral surface has Ra≤5μm and Rz≤20μm, while the outer peripheral surface has Ra≤10μm and Rz≤40μm, creating optimal conditions for different pipe materials
2Ease of manufacture
If conventional grip elements are used on pipes with protective coatings, then installation is simple, but tensile strain resistance is reduced below desirable levels
Solution Approach 1:
The patent creates distinct surface zones with different properties: the inner peripheral surface (facing the pipe) has controlled low roughness for consistent contact, while the outer peripheral surface has higher roughness for enhanced mechanical interlocking with protective coatings on hard pipes
3Ease of manufacture
If cheaper base material is used for the grip element, then manufacturing cost is reduced, but durability and hardness of dents are compromised
Solution Approach 1:
The patent applies surface treatment or coating to the grip element before final assembly. This preliminary action enhances the surface properties (hardness, wear resistance) of the dents and gripping surfaces, allowing cheaper base materials to achieve the durability of expensive materials
Solution Approach 2:
The patent effectively creates a composite structure where the base material provides cost-effective bulk properties while the surface treatment or coating provides enhanced durability and hardness, combining advantages of different material types
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 modified grip element demonstrates improved tensile strain resistance and extended lifespan without maintenance, effectively gripping both hard and soft pipes, including those with protective coatings, while maintaining cost-effectiveness.
Implementation Method 1
prior to pressing the dents out of the plane of the plate, edges of the slit like openings are first subjected to a peening operation. This brings about the advantage to modify the crystal structure of the metal that is used for the grip element, including the structure of the dents that are pressed out of the plane of the grip element. The dents will accordingly be harder
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3D
AI summary
Coupling device (1) for a pipe (2), comprising a sleeve (13) for receiving the pipe (2) and at least one sealing member (5) to provide a seal between the sleeve (13) and the pipe (2), a pressure member (6) for applying a pressure to the sleeve (13) and to the pipe (2), and a grip element (4) extending along at least a part of the perimeter of the pipe (2), wherein the grip element (4) is provided with dents (9) pressed out of the plane of the grip element (4) adjacent to slit like openings (8) punched out of the grip element (4), wherein edges (8') of the slit like openings (8) are subjected to a peening operation.