Boltless Boss Locking via Compression Plates
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Solution Overview
Problem
Traditional fixation methods for pipe bosses in subsea pipeline installations, such as those using integrated flanges and bolts, fail to adequately handle high bending forces and moments, leading to bolt rupture and increased material and cost burdens due to uneven force distribution and tensional stresses.
Innovation Solution
A locking arrangement utilizing annular plates with radially extending surfaces and grooves that convert all forces into compression, eliminating tensional stresses by distributing loads through grooves and flanges, allowing for secure attachment without bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional integrated flange and bolt fixation is used, then the pipe boss can be securely attached to the plate part, but the bolts are subjected to high tensional forces from bending moments that cause bolt rupture
Solution Approach 1:
The invention inverts the force transmission mechanism by replacing tension-based bolt fixation with compression-based plate fixation. Instead of using bolts that are pulled in tension to secure the pipe boss, the invention uses plates that are pressed against the pipe boss in compression, fundamentally reversing the stress state from tensile to compressive.
Solution Approach 2:
The invention replaces the mechanical bolt-tension system with a plate-compression system. The complex multi-bolt tension mechanism is substituted with a simpler plate-based compression mechanism that distributes forces through bearing surfaces rather than relying on bolt tensile strength.
2Strength
If more bolts are used to handle high bending forces, then the attachment strength increases, but the device complexity and material costs increase
Solution Approach 1:
The invention extracts and eliminates the bolts from the fixation system entirely. By removing the bolt mechanism, the complexity associated with multiple high-strength bolts, their installation, and their vulnerability to rupture is completely removed from the system.
Solution Approach 2:
The invention merges the fixation function into the plate structure itself. Instead of using separate bolts in addition to the plate, the plate is designed with integrated features (such as recesses or engagement surfaces) that directly provide the attachment function, combining structural support and fixation into a single component.
3Strength
If heavy high-strength bolts are used to manage high bending moments, then the attachment strength increases, but the material costs and weight increase
Solution Approach 1:
The invention replaces expensive, heavy, high-strength bolts with lighter, simpler plate components. The plate design allows for the use of less expensive materials and reduces the overall weight of the fixation system while maintaining adequate strength through compression-based load distribution.
4Strength
If the pipe boss is designed with an integrated flange, then the attachment strength is improved, but the material costs increase due to large blank diameter
Solution Approach 1:
The invention segments the fixation system into separate components: the pipe boss without an integrated flange, and separate plates that provide the attachment function. This segmentation allows the pipe boss to be manufactured from a smaller blank, reducing material waste, while the plates are added only where needed for fixation.
Data Source
Figure 1A~1B
Figure 2A~3
AI summary
A "boltless" locking arrangement for secure attachment of a boss (1) to a fixed structural part (2) is shown. The boss (1) has a central axis (C) and is extending substantially perpendicular to the plane of the structural part (2) when the parts are assembled. The arrangement includes two substantially radially extending, when viewed relative to the central axis (C), action surfaces (A, B) provided in the external surface (1a) of the boss (1), and at least one annular plate configured body (3) made up by individual segments (3a, 3b). The at least one annular plate configured body (3) is at its radially inner, but external portion (3c) designed to co-operate, or engage with, at least one of the respective two action surfaces (A, B), and at its radially outer, but internal portion (3d) and on opposite side, is abutting the fixed structural part (2).