Subsea Anchoring Fixation Device with Nested Stems
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Solution Overview
Problem
Existing underwater anchoring systems face challenges with complex installation and removal processes, resistance to lateral loading, and high manufacturing costs, particularly due to the design of undercut anchoring piles.
Innovation Solution
A triply nested stem arrangement with releasable couplings allows for a single drive system to simplify installation, enhance structural strength, and improve resistance to lateral loading by distributing axial and rotational motion along the length of the anchor, reducing the complexity of the drive system and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate drives are used for inner and outer stems, then installation control is improved, but device complexity increases
Solution Approach 1:
The patent applies nesting by placing the inner stem inside the outer stem, with both stems rotating together as a unified structure. The cutting elements on the inner stem and the outer stem work in coordination without requiring separate drive mechanisms, thus reducing device complexity while maintaining installation control.
Solution Approach 2:
The patent merges the drive functions by using a single rotational drive that simultaneously rotates both the inner and outer stems. This combining of drive functions eliminates the need for separate motors and control systems, reducing device complexity while preserving installation control through the coupled rotation of both stems.
2Ease of operation
If multiple couplings are used between stems, then rotational control is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the coupling function into simple mechanical features: splines on the inner stem that engage with corresponding splines on the outer stem. This segmentation of the coupling function into discrete, manufacturable features reduces manufacturing cost while maintaining rotational control through the splined engagement.
Solution Approach 2:
The patent uses homogeneous materials and similar mechanical coupling methods throughout the structure. Both stems use comparable splined couplings with identical functional characteristics, simplifying manufacturing processes and reducing costs while ensuring consistent rotational control across the entire assembly.
3Strength
If stems are nested along entire length, then structural strength is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by providing full nesting and coupling only in the regions where structural strength is most critical - specifically where the stems intersect and where loading forces are highest. The nesting is maintained selectively along portions of the stems rather than uniformly along their entire lengths, optimizing structural strength while reducing manufacturing complexity and cost.
Data Source
AI summary
The invention relates to an elongate fixation device (1) for use in subsea anchoring, and a method for installation. The device (1) has a triple nested stem arrangement, the innermost stem (2) of which has a cutter (9) disposed at a distal end and a tapered section (8) located adjacent to and proximally behind the cutter (9). An intermediate stem (3) surrounds at least a central portion of the inner stem (2) and has one or more flareable cutting fingers (7) at its distal end. An outer stem (4) surrounds a proximal portion of the intermediate stem (3). The inner (2) and intermediate (3) stems are coupled by a first releasable coupling (17) which when released allows relative axial motion along a first distance. The outer and intermediate stems are coupled by a second releasable coupling (18) which when released allows relative axial motion along a second distance. The intermediate stem 3 is nested within the outer stem (4), in some cases for at least a majority of the outer stem (4). In some examples, the outer stem (4) has a rotationally driveable portion 10 and the inner stem 2 has a tensioning nut (12) for adjusting the relative axial positions of the inner (2) and outer 4 stems. The tensioning nut (12) and the driveable portion (10) are coupleable to a single rotational drive (23). The invention also relates a method for installation and to installation apparatus (21).