No-Hub Pipe Coupling With Axial Straps Against Separation
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Solution Overview
Problem
Existing no-hub couplings face challenges in providing sufficient axial strength, stiffness, and frictional connection between clamping bands and pipes, leading to issues with axial separation and lateral movement, particularly due to the use of weak rubber gaskets and separate clamping parts that complicate installation and disrupt the coupling function.
Innovation Solution
A no-hub connector design featuring a tubular gasket enclosed by a tubular metal shield with multiple clamps and axial straps that provide adjustable length and gripping projections, ensuring a secure axial connection and improved resistance to separation, while simplifying installation by allowing the connector to be handled as a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber gasket is used to seal the pipe ends, then a fluid tight seal can be achieved, but the axial strength and stiffness of the connection is reduced due to the weak gasket material that may tear under longitudinal force
Solution Approach 1:
The connector is divided into distinct functional components: a soft sealing element (gasket or elastomeric material) for fluid tight sealing, and a rigid structural framework (metal shield, clamping bands, and axial straps) for providing axial strength and stiffness. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The connector combines materials with different mechanical properties: soft elastomeric or rubber materials for sealing surfaces that conform to pipe irregularities, and rigid metal materials (such as stainless steel) for the shield and clamping structures that provide axial strength and resistance to longitudinal forces.
2Strength
If separate clamping parts are used to clamp the gasket and shield, then adjustable clamping force can be applied, but the device complexity increases and installation becomes more difficult
Solution Approach 1:
The clamping bands are integrated with the axial straps to form a unified clamping structure. The axial straps connect the clamping bands together and to the shield, creating a coordinated system that applies clamping force while maintaining axial alignment. This merging reduces the number of separate components and simplifies installation compared to using entirely separate clamping parts.
3Device complexity
If friction alone is used to prevent separation of pipe sections, then a simple connection design is achieved, but the axial strength is insufficient when longitudinal force is great enough to overcome friction
Solution Approach 1:
The clamping bands are tightened around the pipe ends and shield before axial loads are applied, creating preliminary compressive forces and friction. The axial straps are pre-tensioned to establish initial clamping pressure, which enhances frictional resistance to axial separation before service loads are imposed on the connection.
Solution Approach 2:
The clamping bands are designed with a curved or circular cross-section that conforms to the cylindrical shape of the pipe ends and shield. This curvature allows the bands to apply uniform radial clamping pressure around the pipe circumference, maximizing frictional resistance to axial separation while maintaining simple connection geometry.
4Device complexity
If the shield extends only to intermediate clamps, then the connector design is simpler, but axial movement of the shield relative to end clamps may disrupt the coupling function
Solution Approach 1:
The axial straps provide dynamic connectivity between the shield and end clamps, allowing the shield to move axially relative to the end clamps while maintaining functional connection. The straps can accommodate axial displacement through elastic deformation or controlled slippage, ensuring that the coupling function remains intact even when the shield does not extend to the end clamps.
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 design enhances axial strength and stiffness, improves frictional connection, and reduces axial and lateral separation, providing a more reliable and easier-to-install pipe connection by integrating the clamps and shield with axial straps for enhanced resistance to movement.
Implementation Method 1
Axially extending straps are fastened to each ring clamp and also fastened to the shield for each ring clamp that encircles the shield, to axially connect those parts
Implementation Method 2
An inward facing shield surface has optional gripping projections
Implementation Method 3
The ring clamps include first and second end clamps on opposing first and second ends of the connector and first and second intermediate clamps adjacent the respective first and second end clamps but axially inward of the respective first and second end clamps
Data Source
AI summary
A no-hub connector has a tubular gasket enclosed by a tubular shield and includes two end clamps and two intermediate clamps to tighten the connector around the ends of two pipe sections joined by the connector. Axially extending straps are fastened to each ring clamp, and fastened to the shield at the location of each ring clamp encircling the shield. An inward facing shield surface has optional gripping projections and the shield may optionally extend axially past the intermediate clamps to the end clamps. The inward facing surface of the end clamps may have optional gripping projections if the shield does not extend axially to the end clamps.